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Zakład Spektrometrii Mas

Kierownik zakładu:

dr hab. Andrzej Pelc

Pracownicy:

Cytawa Jan
Głuch Krzysztof
Pieńkos Tomasz
Trembaczowski Andrzej

Najważniejsze publikacje: Ukryj abstrakty


  1. A. Pelc,S. Hałas, In vacuo reduction of silver orthophosphate with graphite for high-precision oxygen isotope analysis, Rapid Communications in Mass Spectrometry, 24(), 2010, 2827-2830

  2. S. Hałas,T. Durakiewicz, Is work function a surface or a bulk property?, Vacuum, 85(), 2010, 486-488

  3. T. Pieńkos,S. Hałas,M. Czarnacki, High temperature resistivity determination of high-melting point metals and alloys, Vacuum, 85(), 2010, 498-501

  4. K. Samborska,S. Hałas, 34S and 18O of dissolved sulphate as tracers of hydrogeochemical evolution of the Triassic carbonate aquifer exposed to intense groundwater exploitation (Olkusz-Zawiercie region southern Poland), Applied Geochemistry, 25(), 2010, 1397-1414

  5. T. M. Peryt,S. Hałas,S. P. Hryniv, Sulfur and oxygen isotope signatures of Late Permian Zechstein anhydrites SW Poland: Seawater evolution and diagenetic constrains, Geol. Quarterly, 54(), 2010, 387-399

  6. A. Baran,S. Hałas, Isotope study of therapeutic waters from Horyniec Spa SE Poland, Isotopes in Environmental and Health Studies, 46(), 2010, 454-462

  7. Z. Migaszewski,S. Dołęgowska,S. Hałas,A. Trembaczowski, Stable sulfur isotope ratios in moss species Hylocomium splendes (Hedw.) B.S.G. and Pleurozium schreberi (Brid.) Mitt. from the Kielce area (south-central Poland), Isotopes in Environmental and Health Studies, 46(), 2010, 219-224

  8. J. Wessely-Szponder,B. Majer-Dziedzic,A. Smolira, Analysis of antimicrobial peptides from porcine neutrophils, Journal of Microbiological Methods, 83(), 2010, 8 -12

  9. H. Kucha,E. Schroll,J. G. Raith,S. Hałas, Microbial sphalerite formation in carbonate-hosted Zn-Pb ores Bleiberg Austria: Micro to nano-textural and sulphur isotope evidence, Economic Geology, 105(), 2010, 1005-1023

  10. S. Hałas, A. Wójtowicz, M. Czarnacki, E. Robens, Argon stable isotope concentrations in lunar regolith, Geochronometria, 33(), 2009, 37-39

  11. A. Smolira, M. Smolira, M. Szymańska-Chargot, A. Gruszecka, Computer simulation of bovine insulin clusters ions formation in the MALDI method, Polish Journal of Environmental Studies, 18(), 2009, 3B 337-340

  12. S. Hałas, A. Pelc, New isotope ratio mass spectrometric method of precise d37Cl determinations, Rapid Comm. in Mass Spectrom., 23(), 2009, 1061-1064

  13. K. Głuch, E. Szot, A. Gruszecka, M. Szymańska-Chargot, J. Cytawa, L. Michalak, Kinetic energy release and mean life time metastable ions produced from C3H3N, Vacuum, 83(), 2009, 20-23

  14. A. Gaigalas, S. Hałas, Stable isotopes (H, C, S) and the origin of Baltic amber, Geochronometria, 33(), 2009, 33-36

  15. M. Huber, S. Hałas, A. Piestrzyński, Petrology of gabbroides and isotope signature of sulfide mineralization from Fedorov-Pansky layered mafic intrusion, Kola Peninsula, Russia, Geochronometria, 33(), 2009, 19-22

  16. E. Robens, S. Hałas, Study on the possible existence of water on the Moon, Geochronometria, 33(), 2009, 23-31

  17. K. Jarmołowicz-Szulc, S. Hałas, A. Wójtowicz, Radiometric age analyses of the rocks from the northern envelope of the Karkonosze massif, the Sudetes, Poland – a comparative geochronological study, Geochronometria, 34(), 2009, 33-39

  18. M. Szymańska-Chargot, A. Gruszecka, A. Smolira, K. Bederski, K. Głuch, J. Cytawa, L. Michalak, Formation of nanoparticles and nanorods via UV irradiation of AgNO3 solutions, Journal of Alloys and Compounnds, 486(), 2009, 66-69

  19. L. Wójcik, K. Bederski, K. Głuch, A. Markowski, A. Smolira, J. Cytawa, In memoriam: Prof. Dr. Hab. Leszek Michalak (1956-2008), Vacuum, 83(), 2009, 1-2

  20. J. Aggarwal, F. Böhm, G. Foster, S. Hałas, B. Hönisch, S. -Y. Jiang, J. Kosler, A. Liba, I. Rodushkin, T. Sheehan, J. J. -S. Shen, S. Tonarini, Q. Xie, Ch. -F. You, Z. -Q. Zhao, E. Zuleger, How well do non-traditional stable isotope results compare between different laboratories: results from the interlaboratory comparison of boron isotope measurements, Journal Analitical Atomic Spectrometry, 24(), 2009, 825-831

  21. Migaszewski, Z. Gałuszka, A. Hałas, S. Dołęgowska, S. Dąbek, J. Starnawska, E., Geochemistry and stable sulfur and oxygen isotope ratios of the Podwiśniówka pit pond water generated by acid mine drainage (Holy Cross Mountains south-central Poland), Applied Geochemistry, 23(), 2008, 3620-3634

  22. Migaszewski, Z. Gałuszka, A. Hałas, S. Dąbek, J. Dołęgowska, S. Budzyk, I. Starnawska, E. Michalik, A., Chemical and isotopic variations in the Wiśniówka Mała mine pit water Holy Cross Mountains (south-central Poland), Environmental Geology, (), 2008, DOI 10.1007, s00254-008-1279-z

  23. Głuch, K. Cytawa, J. Michalak, L., Electron impact ionization of acrylonitrile, International Journal of Mass Spectrometry, 273(), 2008, 40100

  24. Głuch, K. Cytawa, J. Michalak, L., Electron impact ionization of acetaldehyde, International Journal of Mass Spectrometry, 273(), 2008, 20-23

  25. Hałas, S., About isotope equilibrium between liquid and vapour phases, Isotopes in Environmental and Health Studies, 44(), 2008, 129-135

  26. Gruszecka, A. Szymańska-Chargot, M. Smolira, A. Cytawa, J. Michalak, L., Role of the support material on laser desorption/ ionization mass spectra, Rapid Communications in Mass Spectrometry, 22(), 2008, 925-929

  27. Pelc, A. Hałas, S., Negative ion source for chlorine isotope ratio measurements, Rapid Communications in Mass Spectrometry, 22(), 2008, 3977-3982

  28. Bojar, A. Hałas, S. Bojar, H. Szaran, J., Isotopic evidence for the origin of an acid sulphate alteration Styrian basin Austria, Terra Nova, 20(), 2008, 45-51

  29. Szymańska-Chargot, M. Gruszecka, A. Smolira, A. Michalak, L., Mass-spectrometric investigations of the synthesis of silver nanoparticles via electrolysis, Vacuum, 82(), 2008, 1088-1093

  30. Gruszecka, A. Szymańska-Chargot, M. Smolira, A. Michalak, L., Laser desorption /ionization of carbon clusters, Vacuum, 82(), 2008, 1083-1087

  31. Hałas, S. Pieńkos, T. Czarnacki, M. Durakiewicz, T., Determination of work function of metals and alloys using diode with spiral anode, Vacuum, 82(), 2008, 1094-1098

  32. Chlebowski, R. Hałas, S., Petrographic-mineralogical and geochemical studies of contemporary sediments developed on the wreck.Petrograficzno-mineralogiczne i geochemiczne badania współcześnie powstałej skały na wraku.rozdział w monografii: THE GENERAL CARLETON SHIPWRECK, 1785WRAK STATKU GENERAL CARLETON, 1785. Gdańsk, Centralne Muzeum Morskie w Gdańsku, (), 2008, 257-278

  33. Szymańska-Chargot, M. Gruszecka, A. Smolira, A. Cytawa, J. Michalak, L., Mass spectrometric investigations of the synthesis of silver nanoparticles via UV irradiation of AgNO3 solutions,Kazimierz Dolny, Poland, Abstracts of VII–th International Conference on Ion Implantation and Other Applications of Ions and Electrons, ION 2008, (), 2008, 116

  34. Smolira, A. Gruszecka, A. Szymańska-Chargot, M. Smolira, M. Michalak, L., Investigations of chicken egg white by matrix-assisted laser desorption/ionization,Kazimierz Dolny, Poland, Abstracts of VII–th International Conference on Ion Implantation and Other Applications of Ions and Electrons, ION 2008, (), 2008, 110

  35. Gruszecka, A. Szymańska-Chargot, M. Smolira, A. Cytawa, J. Głuch, K. Michalak, L., Fragmentation of carbon nanoparticles in LD method,Kazimierz Dolny, Poland, Abstracts of VII–th International Conference on Ion Implantation and Other Applications of Ions and Electrons, ION 2008, (), 2008, 78

  36. Głuch, K. Szot, E. Cytawa, J. Gruszecka, A. Michalak, L., Mean life time measurements of the fragmentation of metastable ions by using double focusing mass spectrometer,Kazimierz Dolny, Poland, Abstracts of VII–th International Conference on Ion Implantation and Other Applications of Ions and Electrons, ION 2008, (), 2008, 26

  37. Smolira, M. Smolira, A. Cytawa, J. Michalak, L., Some aspect of the resolution of TOF mass spectrometer,Kazimierz Dolny, Poland, Abstracts of VII–th International Conference on Ion Implantation and Other Applications of Ions and Electrons, ION 2008, (), 2008, 111

  38. Hałas, S. Bojar, A, Khmelevska, L. Peryt, T., Massive salt deposits as a new isotope archive of earth surface temperatures in geological past, Final Programmae & Abstract Book, Abstract of Joint European Stable Isotope User Meeting “JESIUM 2008”, Presquile de Giens French Mediterranean Coast , (), 2008, 205

  39. Pelc, A. Hałas, S., New method of investigations of chlorine stable isotope ratio, Final Programmae & Abstract Book, Abstract of Joint European Stable Isotope User Meeting “JESIUM 2008”, Presquile de Giens French Mediterranean Coast , (), 2008, 301

  40. Bojar, A. Hałas, S. Bojar, P. Szaran, J., Regional implications of a Miocene acid sulphate alteration, Austria: insights from the H, O, S and K-Ar isotopic record,Geophysical Research Abstracts, Abstract of EGU General Assembly 2008, Geophysical Research , 10(), 2008, EGU2008-A-10640

  41. Piotrowska, N. Pazdur, A. Hałas, S. Rutkowski, J., Carbon and oxygen isotope record in carbonate sediments of Lake Wigry (NE Poland),Geophysical Research Abstracts, IG1-1MO5P, Abstract of EGU General Assembly 2008, Geophysical Research , 10(), 2008, EGU2008-A-10640

  42. Hałas, S. Pelc, A., New IRMS method of precise δ37Cl measurement,Geophysical Research Abstracts, Abstract of EGU General Assembly 2008, Geophysical Research , 10(), 2008, EGU2008-A-10640

  43. Jarmołowicz-Szulc, K. Hałas, S. Wójtowicz, A., Analiza wieku radiometrycznego skał północnej osłony masywu Karkonoszy – studium porównawcze, Lublin, Abstracts of All-Polish Scientific Conference “Dating of Minerals and Rocks X”, (), 2008, 7-10

  44. Gaigalas, A. Hałas, S., Stable isotope (H, C, S) composition and the origin of Baltic amber, Lublin, Abstracts of All-Polish Scientific Conference “Dating of Minerals and Rocks X”, (), 2008, 11-14

  45. Hałas, S. Wójtowicz, A. Czarnacki, M., Argon isotope abundances in lunar regolith samples, Lublin, Abstracts of All-Polish Scientific Conference “Dating of Minerals and Rocks X”, (), 2008, 17

  46. Pelc, A. Hałas, S., Nowa metoda analizy izotopów stabilnych chloru, Lublin, Abstracts of All-Polish Scientific Conference “Dating of Minerals and Rocks X”, (), 2008, 33

  47. Huber, M. Hałas, S. Piestrzyński, A., Charakterystyka petrologiczna gabroidów z warstwowanych intruzji fiodoro-panskiego masywu na plw. Kolskim (Rosja), Lublin, Abstracts of All-Polish Scientific Conference “Dating of Minerals and Rocks X”, (), 2008, 47-48

  48. Piotrowska, N. Pazdur, A. Hałas, S. Rutkowski, J., Carbon and oxygen isotope record in carbonate sediments of lake Wigry (NE Poland), Lublin, Abstracts of All-Polish Scientific Conference “Dating of Minerals and Rocks X”, (), 2008, 58-59

  49. Szymańska-Chargot, M. Gruszecka, A. Smolira, A. Cytawa, J. Michalak, L., Powstawanie klasterów srebra w procesie laserowej desorpcji/jonizacji różnych związków srebra, Janów Lubelski, IV Kongres Polskiego Towarzystwa Próżniowego, VIII Krajowa Konferencja Techniki Próżni, (), 2008, O-34

  50. Smolira, A. Gruszecka, A. Szymańska-Chargot, M. Michalak, L., Masowo-spektrometryczne badania olejów roślinnych metodą MALDI, Janów Lubelski, IV Kongres Polskiego Towarzystwa Próżniowego, VIII Krajowa Konferencja Techniki Próżni, (), 2008, P- 06

  51. Gruszecka, A. Szymańska-Chargot, M. Smolira, A. Wójcik, L., Masowo-spektrometryczne badania desorpcji laserowej klasterów węgla, Janów Lubelski, IV Kongres Polskiego Towarzystwa Próżniowego, VIII Krajowa Konferencja Techniki Próżni, (), 2008, O-15

  52. Głuch, K. Szot, E. Cytawa, J. Michalak, L., Double focusing mass spectrometer in investigations of ionization processes, Janów Lubelski, IV Kongres Polskiego Towarzystwa Próżniowego, VIII Krajowa Konferencja Techniki Próżni, (), 2008, O-30

  53. Pelc, A. Hałas, S., Spektrometr mas do analizy izotopowej chloru i bromu, Janów Lubelski, IV Kongres Polskiego Towarzystwa Próżniowego, VIII Krajowa Konferencja Techniki Próżni, (), 2008, 0-05

  54. Hałas, S. Pieńkos, T., O pomiarach pracy wyjścia stopów metali trudnotopliwych, Janów Lubelski, IV Kongres Polskiego Towarzystwa Próżniowego, VIII Krajowa Konferencja Techniki Próżni, (), 2008, 0-13

  55. Dąbek, J. Hałas, S., Spektrometr mas z dwuwłóknowym, termoemisyjnym źródłem jonów do analizy izotopowej litu, boru, renu i osmu, Janów Lubelski, IV Kongres Polskiego Towarzystwa Próżniowego, VIII Krajowa Konferencja Techniki Próżni, (), 2008, 0-35

  56. Pieńkos, T. Czarnacki, M. Hałas, S., Wyznaczenie termoelektrycznej pracy wyjścia hafnu, Janów Lubelski, IV Kongres Polskiego Towarzystwa Próżniowego, VIII Krajowa Konferencja Techniki Próżni, (), 2008, P-21

  57. Hałas, S., Analiza izotopowa litu, boru i chloru – nowe możliwości dla geochemii, Kraków, Pierwszy Polski Kongres Geologiczny , (), 2008,

  58. Pelc, A. Scheier, P. Mark, T.D., Low-energy electron interaction with nitrobenzene: C6H5NO2, Vacuum, 81(10), 2007, 1180-1183

    Abstract:
    Low-energy electron attachment to C6H5NO2 (nitrobenzene) in the gas phase is reported in the electron energy range from about 0 up to 10eV with an energy resolution of 120 meV. Dissociative and nondissociative electron attachment to nitrobenzene were observed. From the numerous ions observed, the two most abundant were NO2- and C6H5NO2-. Based on comparison of the abundance of studied ions with Cl- in the dissociative electron attachment to CCl4 at 0.8 eV, estimates of cross sections for the all observed ions were obtained for the first time (e.g. sigma(NO2-) = 4.6 x 10(-20) m(2) and sigma(C6H5NO2-) = 3.8 x 10(-21) m(2)). (c) 2007 Elsevier Ltd. All rights reserved.

  59. Głuch, K. Matt-Leubner, S. Echt, O. Scheier, P. Mark, T.D., Metastable C3H52+ produced by electron impact of propane, Vacuum, 81(10), 2007, 1129-1132

    Abstract:
    Metastability of C3H52+ ions formed by electron impact ionization of propane was monitored with the help of a magnetic mass spectrometer of reversed geometry (BEE geometry). In the present paper, we report decay reactions resulting in C3H4+ + H+, and C3H3+ + H-2(+). We observed fragment ions which are formed with high kinetic energy. Mass analyzed ion kinetic energy (MIKE) scan technique in the third field free region of the mass spectrometer was applied to identify the fragment ions and determine their kinetic energy release (KER). An average KER of 1.6 +/- 0.3 eV for the first reaction and 0.67 +/- 0.15 eV for the second reaction are reported. (c) 2007 Elsevier Ltd. All rights reserved.

  60. Peryt, T.M. Makhnach, A.A. Halas, S. Petrychenko, O.Y. Gulis, L.F. Abravets, S.M., Sulfur isotopes in anhydrites from the Upper Devonian Prypiac' and Dnipro-Donets Basins (Belarus and Ukraine), Carbonates And Evaporites, 22(1), 2007, 43-54

    Abstract:
    Upper Devonian evaporite rocks worldwide record a marked sulfur isotope excursion to heavier delta S-34 values. New delta S-34 data from anhydrite laminae in halite, anhydrite in water-insoluble residue in halite and sulfate from massive sulfate units in evaporite sequences of the Prypiac' and Dnipro-Donets Basins of Betarus and Ukraine are presented. The mean 8345 is 27.6 parts per thousand +/- 3.0 %o (n = 60) with a range from 21.9 parts per thousand to 35.6 parts per thousand. The mean values for Frasnian and Famennian evaporites are similar: 27.5 parts per thousand +/- 3.8 parts per thousand (n = 30) and 27.7 %o +/- 1.9 parts per thousand (n = 30), respectively. The rocks formed in a restricted basin but its parent waters had a marine source. Bacterial sulfate reduction was the dominant process controlling delta S-34 of Upper Devonian anhydrite and pyrite although also disproportionation processes and secular variation played an important role. True secular isotope variation is indicated between stratigraphic units, and a range of c. 24-29 parts per thousand is assumed to be representative for oceanic sulfate of this time. New data from the Lower Eifelian suggest that the value of c. 15 parts per thousand was representative for oceanic sulfate of Eifelian time, and this indicates the increase of delta S-34 values of oceanic sulfate by 12 parts per thousand during ca. 11 Ma. Subsequently, delta S-34 values show high plateau of 27 parts per thousand during ca. 12 Ma (Early Frasnian to Late Famennian) with some oscillation reflected in the mean values for particular evaporite units.

  61. Fedor, J. Echt, O. Gluch, K. Matt-Leubner, S. Scheier, P. Märk, T.D., On the role of the II(1/2g) state in spontaneous dissociation of krypton and xenon dimer ions, Chemical Physics Letters, 437(), 2007, 183-188

  62. Hałas, S., Low-blank crucible for argon extraction from minerals at temperatures up to 1550oC, Geochronometria, 27(), 2007, 1-3

  63. Turniak, K. Hałas, S. Wójtowicz, A., New K-Ar cooling ages of granitoids from the Strzegom-Sobótka massif, SW Poland, Geochronometria, 27(), 2007, 5-9

  64. Paul, Z. Hałas, S. Wójtowicz, A., New data on the post-impact material in radiolarian horizons in outer flysh carpathians and search for a source crater, Geochronometria, 27(), 2007, 17-22

  65. Dąbek, J. Hałas, S., Physical foundations of rhenium-osmium method – a review, Geochronometria, 27(), 2007, 23-26

  66. Huber, M. Hałas, S. Sikorska, M., Evolution of prehnite-albite-calcite veins in metamorphic rocks from the Lapland Granulite Belt (Kandalaksha region of Kola Peninsula), Geologija, 59(), 2007, 1-7

  67. Kasprzyk, A. Pueyo, J.J. Hałas, S. Fuenlabrada, J.M., Sulphur, oxygen and strontium isotope compositions of Middle Miocene (Badenian) calcium sulphates from the Carpathian Foredeep, Poland: palaeoenvironmental implications, Geological Quarterly, 51(), 2007, 285-294

  68. Hałas, S. Szaran, J. Czarnacki, M. Tanweer, A. , Refinements in BaSO4 to CO2 preparation and δ18O calibration of the sulfate reference materials NBS-127, IAEA SO-5 and IAEA SO-6, Geostandars and Geoanalytical Research, 31(), 2007, 61-68

  69. Rajchel, J. Rajchel, J. Szaran, J. Hałas, S., Reply to the „Comment on the paper ‘Sulphur isotopic composition of H2S and SO2-4 from mineral springs in the Polish Carpathians’”, Isotopes in Environmental and Health Studies, 43(), 2007, 78-79

  70. Feil, S. Gluch, K. Bacher, A. Matt-Leubner, S. Bohme, D. K. Scheier, P. Mark, T. D., Cross sections and ion kinetic energy analysis for the electron impact ionization of acetylene, Journal of Chemical Physics, 124(21), 2006, art. no.-214307

    Abstract:
    Using a Nier-type electron impact ion source in combination with a double focusing two sector field mass spectrometer, partial cross sections for electron impact ionization of acetylene are measured for electron energies up to 1000 eV. Discrimination factors, for ions are determined using the deflection field method in combination with a three-dimensional ion trajectory simulation of ions produced in the ion source. Analysis of the ion yield curves obtained by scanning the deflectors' allows the assignment of ions with the same mass- to-charge ratio to specific production channels on the basis of their different kinetic energy distributions. This analysis also allows to determine, besides kinetic energy distributions of fragment ions, partial cross sections differential in kinetic energy. Moreover a charge separation reaction, the Coulomb explosion of the doubly charged parent ions C2H2++ into the fragment ions C2H+ and H+, is investigated and its mean kinetic energy release (< KER > = 3.88 eV) is deduced. (c) 2006 American Institute of Physics.

  71. Feil, S. Gluch, K. Denifl, S. Zappa, F. Echt, O. Scheier, P. Mark, T. D., Metastable dissociation and kinetic energy release of helium clusters upon electron impact ionization, International Journal of Mass Spectrometry, 252(2), 2006, 166-172

    Abstract:
    Neutral helium clusters, formed in a supersonic beam, are subjected to electron impact ionization. We report resolved size distributions of cations of size n <= 300. The distributions show the well established anomalies at n = 10 and 14, but none for larger sizes. MIKE scans of the cluster ions confirm the anomalies at n = 10 and 14, and another one at n = 7. Surprisingly broad distributions of fragment ions are observed for parent sizes 15 <= n <= 30. These findings are attributed to radiative heating. The kinetic energy released upon loss of one helium atom (KER) has been measured. The values drop below I meV for n > 20. Neither the metastable fragment distribution nor the KER data provide evidence for the release of large, quantized energies that one would expect for relaxation of any long-lived vibronic states of the ionic core. (C) 2006 Elsevier B.V. All rights reserved.

  72. Feil, S. Gluch, K. Matt-Leubner, S. Echt, O. Lifshitz, C. Cao, B. P. Wakahara, T. Akasaka, T. Scheier, P. Mark, T. D., The stability of singly and multiply charged La@C-80 and La@C- 82 ions determined from kinetic energy release measurements, International Journal of Mass Spectrometry, 249(), 2006, 396-402

    Abstract:
    We have measured the kinetic energy release distributions for unimolecular C-2 loss from singly and multiply charged endohedral La@(z+)(80) and La@C-80(z+) ions for charge states z = 1-3. Using finite heat bath theory, we deduce the dissociation energies for loss of C-2. The charge state z has no statistically significant effect on the dissociation energies. The dissociation energies of endohedral fullerene ions are larger than those of the corresponding empty fullerene, ions by a few tenths of an electron volt, but the differences are barely statistically significant. The small differences also imply that the complexation energies of La@C- n(z+) and La@C-n-2(z+) are identical within the experimental errors, for n = 80 and 82 and all charge states. (c) 2005 Elsevier B.V. All rights reserved.

  73. Halas, S., 100 years of work function, Materials Science-Poland, 24(4), 2006, U67-U83

    Abstract:
    This paper traces early inquires on the nature of the work function (WF). Much attention was paid to the papers published by Einstein (1905), Richardson (1901), Jentzsch (1908), Debye (1910), Schottky (1914) and Langmuir (1916). Those authors assumed that the image force, introduced already by Thomson for macroscopic bodies, may be the main reason for the barrier at the metal surface. The formula derived by Schottky ( 1914) is still used for calculation of the lowering of the surface barrier in presence of an external electric field. In further development of surface physics, however, much emphasis was paid to the role of a dipole layer. However, at the end of 20th century the idea of the image potential as the main contribution to WF was restored by Brodie (1995) and subsequently improved by Halas and Durakiewicz (1998). In these theories a distance d from which the image force can be integrated is found from the uncertainty principle and from the length of spontaneous metallic plasma polarization, respectively. The last approach has appeared to be very useful in calculation of WF of conducting compounds and ionization potentials of metallic clusters.

  74. Krouse, H. R. Parafiniuk, J. Nowak, J. Halas, S., Millimeter scale variations in the isotopic composition of vein sulphide minerals in the Kupferschiefer deposits, Lubin area, SW Poland, Isotopes in Environmental and Health Studies, 42(4), 2006, 327-333

    Abstract:
    A slice of black shale rock cut by various metal sulphide veins of different generations from the Kupferschiefer deposits of Lubin, Poland was subjected to bombardment in a Laser Microprobe Combustion Reactor to produce SO2 for S-isotope analyses. The delta S-34 values ranged from - 22 to - 29% consistent with previous findings using conventional IRMS and attributable to primary generation of H2S by bacterial sulphate reduction. Systematic trends in delta S-34 values of a few per mil over distances of the order of mm attest to low temperatures of mineralization with accompanying change in the isotope composition of the fluids due to kinetic or equilibrium isotope fractionation.

  75. Szczepanek, M. Pazdur, A. Pawelczyk, S. Bottger, T. Haupt, M. Halas, S. Bednarz, Z. Krapiec, M. Szychowska-Krapiec, E., Hydrogen, carbon and oxygen isotopes in pine and oak tree rings from Southern Poland as climatic indicators in years 1900-2003, Geochronometria, 25(), 2006, 67-76

    Abstract:
    Carbon, oxygen and hydrogen stable isotopes in tree rings are sensitive indicators of climate changes. We have measured carbon, oxygen and hydrogen isotope ratios in alpha-cellulose extracted from annual rings of pine (Pinus sylvestris L.) and oak (Quercus robur L.) growing in the Niepolomice Forest, Southern Poland. The presented isotope records cover the period 1900-2003. In this paper we compare the values of delta C-13, delta O-18 and delta H-2 observed in the wholewood of pine and in the latewood of oak with meteorological data (temperature, precipitation and sunshine). The highest significant values of correlation coefficients calculated between delta C-13 and the meteorological data are: -0.26 for temperature, 0.25 for precipitation and 0.41 for sunshine. On the basis of our investigations we deduced that pine is a more sensitive indicator of environmental changes than oak. Our investigation proves that the best indicators are: hydrogen for summer temperature and oxygen for summer precipitation. We noticed a rapid decrease of pine delta C-13 values in 1966 from -22.46 parts per thousand to -24.64 parts per thousand.

  76. Halas, S., Double-vacuum crucible for temperatures upto 1600 degrees C, Journal of Thermal Analysis and Calorimetry, 86(1), 2006, 31-33

    Abstract:
    A new design of dual-vacuum crucible (Staudacher type) is described. The lower and upper part of the crucible is made of tantalum and titanium, respectively. The lower part is heated by a tantalum wire coil inserted into a helix furrow made in a thick-walled insulating cylinder. This cylinder was made from a machineable boron nitride ceramic. By means of this, the crucible may be safely heated in vacuum up to 1600 degrees C.

  77. Kovalevych, V. M. Zang, W. L. Peryt, T. M. Khmelevska, O. V. Halas, S. Iwasinska-Budzyk, I. Boult, P. J. Heithersay, P. S., Deposition and chemical composition of Early Cambrian salt in the eastern Officer Basin, South Australia, Australian Journal of Earth Sciences, 53(4), 2006, 577-593

    Abstract:
    Lower Cambrian salt deposits in the eastern Officer Basin occur in troughs along the western and northwestern margin of the Gawler Craton, and are interpreted to have been deposited in marginal to restricted marine environments. The salt horizons in two drillholes (Manya 6 (373554E, 6938478N: GDA94) and Wilkinson 1 (263545E, 6693435N: GDA94)) were studied utilising multiple techniques including mineralogical investigation, fluid inclusion and isotopic analysis. New data on Br values of 19 salt samples provide evidence of marine origin for the salt. Abundant two-phase (gas-liquid) inclusions and poor preservation of primary inclusions indicate intensive post- depositional recrystallisation. Homogenisation studies of fluid inclusions in halite from Manya 6 suggest that the upper part of the salt-bearing strata (Ouldburra Formation) has been heated to 80 C, whereas the lower part reached even higher temperatures. This heating event may be related to the Devonian-Carboniferous Alice Springs Orogeny. The chemical composition of fluid inclusions in Manya 6 and Wilkinson 1 samples indicates that parent brines were Ca-rich and SO4-poor, whereas modern seawater is SO4-rich and Ca-poor. Such a composition is similar to that recorded in the Lower Cambrian halite from the East Siberia Basin.

  78. Halas, S. Durakiewicz, T., Physical foundations of the oxide cathodes, Applied Surface Science, 252(18), 2006, 6119-6121

    Abstract:
    A novel explanation of the low values of work function in case of activated (partly deoxidized) polycrystalline oxides of alkali and alkaline earth metals is offered. Use of the metallic plasma model to the conducting oxides leads to the following values (in eV): 1.00, 1.67, 1.50, 1.44, 1.46 and 1.59 for activated Cs2O, CaO, SrO, BaO, Y2O3 and La2O3, respectively. The main reason of low work function of the oxide cathodes is very low density of free electrons in the emitting surface layer. (c) 2006 Elsevier B.V All rights reserved.

  79. Vokal-Nemec, B. Szaran, J. Trembaczowski, A. Halas, S. Dolenec, T. Lojen, S., Sulphate sources in the Sava and Ljubljanica rivers, Slovenia, inferred from sulphur and oxygen isotope compositions, Aquatic Geochemistry, 12(3), 2006, 199-220

    Abstract:
    Measurements were made of sulphur and oxygen isotope ratios of sulphate in some Slovenian rivers, lakes and tap waters. delta S-34 ranged from -0.2 to +13.3 parts per thousand, delta O-18 ranged from + 4.9 to + 13.6 parts per thousand, and the sulphate content varied from 0.8 to 41.4 mg/L. Rivers. owing from the Julian Alps contain a very low amount of sulphate that is leached from a thin horizon of soil by rain. As confirmed by their low delta O-18 values, these sulphates do not enter the rivers directly in rain, but arise from biochemical cycling in the soil. The low delta S-34 of this sulphate indicates that it originates from the oxidation of sedimentary sulphides. The evolution of sulphates along the river course was investigated for the Sava and Ljubljanica rivers. The variations observed in sulphate from the waters studied result from variations in the contribution of sulphates of different origin. Downstream the Sava River sulphate is depleted in the heavy isotopes of both sulphur and oxygen, with delta-values gradually tending toward the delta-values of groundwater sulphates in the watershed. In contrast, the delta-values of sulphate in the Ljubljanica River are almost constant and similar to those of sulphate in local groundwater. Introduction of water from Italian and Slovenian mines was recorded in the Soca River, where the lowest delta S- 34 value of sulphate sulphur (-0.2 parts per thousand) was observed. In addition, the influence of sulphate from the oxidation of sedimentary sulphides was recorded in the Sotla River. No evidence was found for introduction of sulphate from factories.

  80. Durakiewicz, T. Sikora, J. Halas, S., Work function variations of incandescent filaments during self- cooling in vacuum, Vacuum, 80(8), 2006, 894-898

    Abstract:
    A novel method of dynamic measurement of work function (WF) variations of hot metal filaments is described. It is essential in this method that electron emission current (I-e) is recorded during filament self-cooling when no heating power is supplied, thereby I-e is not disturbed by the potential gradient along the filament. WIF shift due to the presence of a low-pressure gas, where the main active compounds are O-2 and H2O, is calculated from an equation derived on the basis of the Richardson formula. The relative increase of WF found by this method was 5 times larger for tungsten than that for tantalum over the entire temperature range from 900 to 1800 K. Our method may be used in research studies of adsorption-related phenomena on metallic surfaces at high temperatures. (c) 2006 Elsevier Ltd. All rights reserved.

  81. Gladyszewski, G. Chocyk, D. Proszynski, A. Pienkos, T., Stress evolution during intermittent deposition of metallic thin films, Microelectronic Engineering, 83(11-12), 2006, 2351-2354

    Abstract:
    Copper, silver and gold thin films were deposited on Si(001) substrates at room temperature in UHV vacuum system. The process was intermittent in a periodic way i.e. for each sublayer the deposition was interrupted for about 10 min. The total force per unit width (F/w) was in situ determined in deposited films by the use of the substrate curvature measurement method with laser scanning technique. Significant stress evolution during the interruption periods was observed for Cu and Ag layers whereas no evolution was observed for Au layers. Differences in the growth character are discussed basing on the Volmer-Weber growth model. (c) 2006 Elsevier B.V. All rights reserved.

  82. Feil, S. Echt, O. Gluch, K. Hasan, V. G. Matt-Leubner, S. Tepnual, T. Grill, V. Bacher, A. Scheler, P. Mark, T. D., Metastable dissociation of doubly charged ions produced from toluene: Kinetic energy release upon charge separation and H-2 elimination, Chemical Physics Letters, 411(4-6), 2005, 366-372

    Abstract:
    Doubly charged ions produced by electron impact ionization of toluene undergo metastable decomposition. We have determined decay channels for C7Hy2+ (y = 6-8) and the average kinetic energy release (KER) by applying the MIKE scan technique. We observe several reactions that have not been reported previously, including H-2 elimination from C7H82+ The KER distribution for H, loss shows no evidence for a reverse barrier. The average KER is < 0.1 eV; it exhibits a distinct time dependence and isotope effect. On the other hand, some charge separation reactions reported previously in the literature are likely due to isotopic interference. (c) 2005 Elsevier B.V. All rights reserved.

  83. Concina, B. Gluch, K. Matt-Leubner, S. Echt, O. Scheier, P. Mark, T. D., Metastable fractions and dissociations energies for fullerene ions C-n(+), 42 <= n <= 70, Chemical Physics Letters, 407(4-6), 2005, 464-470

    Abstract:
    Metastable fractions for the dissociation of fullerene cations C-n(+) -> C-n-2(+) + C-2 (42 <= n <= 70) have been measured in a three-sector-field mass spectrometer. They have been determined with the same experimental setup as the kinetic energy release data published recently. A statistical model which includes cooling by radiation as required by the timescale of the experiment is used to deduce dissociation energies from the metastable fractions. The results are compared with values extracted from our kinetic energy release data and other experiments. (c) 2005 Elsevier B.V. All rights reserved.

  84. Peryt, T. M. Bula, Z. Halas, S. Olszewska, B. Pluta, I. Slodkowska, B., Non-marine evaporites in the Lower Miocene of Upper Silesia (Carpathian Foreland Basin, Poland), Geologica Carpathica, 56(4), 2005, 327-336

    Abstract:
    A continual record of Eggenburgian to Late Badenian deposition, mostly in non-marine environments during the Early Miocene and in marine settings during the Middle Miocene time periods, was studied in the Woszczyce IG1 borehole (Zawada Basin, the Upper Silesia segment of the Carpathian Foreland Basin). In addition to the earlier-described Early Miocene foraminiferal assemblages, a Late Ottnangian pollen assemblage, which can be correlated with the MF4 Zone from Slovakia was found. Anhydrite-bearing deposits occur some 25 m below the Lower Badenian Skawina Formation. The foraminifers found immediately above the anhydrite-bearing complex and the redeposited foraminifers recorded in the lowermost part of the complex indicate its Karpatian age. The anhydrite is replacing gypsum, which originally formed displacive lenticular crystals within claystones and siltstones. The delta(34)S values of anhydrite (+2.17 parts per thousand to +9.2 parts per thousand, average +4.4 parts per thousand) are considerably lower and the 8180 values (+18.0 parts per thousand to +22.0 parts per thousand, average +20.1 parts per thousand) are considerably higher than the values characteristic for Miocene marine sulphates. On the other hand, the range of delta(34)S values found in the anhydrites of the Woszczyce IG1 borehole is similar to the range recorded in the sulphur from Carboniferous coals. The sulphate was recycled and evaporite deposits in the Woszczyce IG1 borehole, and thus in the entire Zawada Basin, formed from recycled solutes. Thus, the anhydrite-bearing sequence originated in a non-marine environment, in which periodically saline conditions prevailed.

  85. Szaran, J. Dudziak, A. Trembaczowski, A. Niezgoda, H. Halas, S., Diurnal variations and vertical distribution of delta C-13, and concentration of atmospheric and soil CO2 in a meadow site, SE Poland, Geological Quarterly, 49(2), 2005, 135-144

    Abstract:
    We provide the results of 24-hour observations made in a meadow site located in a small river valley in Central Europe. Samples of atmospheric air were taken from three horizons: near the soil (0.05 m), in the grass (0.5 m) and above the meadow (2 m) at two-hour intervals. At the same time, samples of soil air were collected from two horizons: -0.1 and -0.5 m. We have found a variation of delta(13)C above the ground from -6 parts per thousand during the day to -20 parts per thousand late at night accompanied by variations in CO2 concentration from 270 ppm during the day, to various levels late at night at different heights above the ground. The maximum concentration was 1430 ppm at the ground level. The correlation coefficient between delta(13)C and reciprocal of concentration was the highest (R-2 = 0.984) for the samples collected 2 m above the ground, the regression line clearly indicating CO2 mixing from the two sources: atmospheric and biogenic reservoirs. The intercept of the mixing line yields delta(13)C -23.0 parts per thousand for the biogenic CO2. In contrast, the diurnal variations in the soil were relatively small, delta(13)C varied from -21.6 to -23.4 parts per thousand, while CO2 concentration from 4300 to 8200 and from 24 700 to 34 500 ppm at depths of 0.1 m and 0.5 m respectively, which is less than 2-fold. Small diurnal variations are characteristic of dry soils, where delta(13)C is weakly correlated with CO2 concentration (in our case R-2 was 0.30 and 0.54, respectively).

  86. Pazdur, A. Korput, S. Fogtman, M. Szczepanek, M. Halas, S. Krapiec, M. Szychowska-Krapiec, E., Carbon-13 in alpha-cellulose of oak latewood (Jedrzejow, Southern Poland) during the Maunder Minimum, Geological Quarterly, 49(2), 2005, 165-171

    Abstract:
    We have studied the delta(13)C signature in latewood alpha- cellulose of an ancient oak (Quercus robur L.) from a Cisterian Abbey belfry in Jedrzejow (Southern Poland). The time scale for the delta(13)C record during 1631-1765 AD was built on the basis of detailed dendrochronology studies. Techniques available for extraction of alpha-cellulose from small samples have been used, the mean value of alpha-cellulose extraction efficiency being ca. 35%. In the delta(13)C record of alpha- cellulose the cooling between 1650-1700 AD is clearly visible as a decrease of about 1.5 parts per thousand. This period is consistent with the interval of the lowest solar activity between 1645 and 1715 AD, which is known as the Maunder Minimum. Anti-correlation between delta(13)C and Delta(14)C during the Maunder Minimum was observed but Delta(14)C record is delayed by about 30 years with respect to the Maunder Minimum.

  87. Peryt, T. M. Halas, S. Kovalevych, V. M. Petrychenko, O. Y. Dzhinoridze, N. M., The sulphur and oxygen isotopic composition of Lower Cambrian anhydrites in East Siberia, Geological Quarterly, 49(2), 2005, 235-241

    Abstract:
    Published sulphur and oxygen isotope age curves for the late Neoproterozoic-Early Cambrian time interval have been based on studies of sulphate intervals of the East Siberian salt giant. We report here on sulphur and oxygen measurements for sulphate dispersed in, or forming laminae in, the rock salt deposits in all Lower Cambrian basins of East Siberia. Sulphur isotope data for 26 samples of Lower Cambrian anhydrites from East Siberia range from +22.6 to +34.5 parts per thousand. No difference was observed between different suites and between samples taken from anhydrite intercalations in rock salt and from water- insoluble residue in rock salt. Oxygen isotope data for 25 anhydrite samples range from +12.4 to + 17.8 parts per thousand, and thus delta(18)O values have a smaller range of variation (5.5 parts per thousand) than delta(34)S (11.8 parts per thousand) over the entire set of Lower Cambrian anhydrites. The great delta(34)S variability observed in the Lower Cambrian of Siberia seems to reflect mixing of sulphates coming from the ocean and due to the riverine input. The lowest delta(18)O values may indicate the input values from both the sources, whilst the highest value may result from isotope exchange between SO42- and water. Our results combined with data provided by previous workers could indicate a clear stratigraphic trend in delta(34)S values, with a remarkable fall of ca. 9 parts per thousand in delta(34)S value during the earliest Cambrian and then a slight rise in delta(34)S values in the younger part of Early Cambrian. However, if only the highest values are taken, the measured values are compatible with seawater delta(34)S >= 30 parts per thousand during the entire Early Cambrian. Sulphur isotopic composition of sulphate minerals did not become heavier from the sulphate stage toward the chloride stage.

  88. Pelc, A. Sailer, W. Scheier, P. Mark, T. D., Generation of (M-H)(-) ions by dissociative electron attachment to simple organic acids M, Vacuum, 78(2-4), 2005, 631-634

    Abstract:
    Low energy (similar to 0-3.5 eV) dissociative electron attachment to the simplest organic acids (formic, acetic and propanoic) is studied at high electron energy resolution (60 meV) by means of mass spectrometric detection of the product anions. For all (M-H)(-) negative fragment ions produced, vibrational structure in the attachment spectra is observed. The energy gaps between the vibrational levels in HCOO-, CH3COO- and CH3CH2COO- are derived (ranging from 250 +/- 60 meV up to 350 +/- 60 meV). (c) 2005 Elsevier Ltd. All rights reserved.

  89. Chocyk, D. Proszynski, A. Gladyszewski, G. Pienkos, T. Gladyszewski, L., Post-deposition stress evolution in Cu and Ag thin films, Optica Applicata, 35(3), 2005, 419-424

    Abstract:
    Evolution of stresses in thin Cu and Ag films after deposition by thermal evaporation in UHV system is studied. Thin films were deposited on 100 pm thick Si substrate at room temperature. Deposition rates for the Cu and Ag films were 0.5 angstrom/s and 0.9 angstrom/s, respectively. The total thickness ranged from 7.7 up to 109 nm. The average stress in the films was determined by measuring the radius of samples curvature. The behavior of stress evolution curves is explained by two mechanisms of stress generation: filling grain boundaries and islands coalescence.

  90. Pienkos, T. Gladyszewski, L. Proszynski, A. Chocyk, D. Gladyszewski, G., Determination of surface waviness using radius of curvature measurement with laser scanning technique, Optica Applicata, 35(3), 2005, 503-507

    Abstract:
    A method for obtaining the shape of a surface investigated with a laser scanning curvature measurement is presented. Additional simple analysis of raw experimental data allows one to determine waviness of the sample. The accuracy of the method and comparison of the results obtained with the method and commercial profilometer are also described.

  91. Proszynski, A. Chocyk, D. Gladyszewski, G. Pienkos, T. Gladyszewski, L., Measurement of stress as a function of temperature in Ag and Cu thin films, Optica Applicata, 35(3), 2005, 517-522

    Abstract:
    Stress measurements of 23 nm copper films and 93 nm silver films on Si (100) have been performed during thermal cycling between RT and 450 degrees C. The changes in stress versus temperature are interpreted. The effects of treatment on microstructure and composition are studied by X-ray diffraction.

  92. Chocyk, D. Zientarski, T. Proszynski, A. Pienkos, T. Gladyszewski, L. Gladyszewski, G., Evolution of stress and structure in Cu thin films, Crystal Research and Technology, 40(4-5), 2005, 509-516

    Abstract:
    Evolution of stresses developing in Cu thin films during and after deposition by thermal evaporation in LTHV system is studied. Thin films were deposited on 100 pm thick Si substrate at room temperature. Deposition rates for the films were changed between 0.2 angstrom/s and 2.0 angstrom/s, while the total thickness was changed from 7.7 nm to 155 nm. Deformation analysis of crystalline lattice and microstructure was performed by x-ray diffraction measurements (theta-2 theta scans, "sin(2)psi" method). The surface morphology of film was studied by atomic force microscopy. The average stress in the films was determined by measuring the radius of curvature of samples. For thin films three stages of stress evolution (compressive, tensile and compressive) were we distinguished. This behavior is characteristic for materials with a Volmer- Weber mode. A three-dimensional molecular dynamics technique was applied for simulating the stress calculation during thin film growth. The results obtained from the simulation are consistent with the experimental results.

  93. Smolira, A. Szymanska, M. Jartych, E. Calka, A. Michalak, L., Structural transformations in graphite induced by magneto- mechanical-milling in hydrogen atmosphere, Journal of Alloys and Compounds, 402(1-2), 2005, 256-262

    Abstract:
    Laser desorption time-of-flight mass spectrometry, X-ray diffraction and Mossbauer spectroscopy methods were used for characterization of phase transformations induced in graphite during controlled reactive ball milling in hydrogen atmosphere. During milling, the crystalline structure of the graphite transformed to nanostructure as proved by X-ray diffraction studies. The hydrogen storage capacity of the nanostructured graphite depends strongly on the energy of milling process and reached 2.718 wt.% in this study. The mass spectrometry method revealed in the milling products a variety of bare carbon clusters as well as hydrogenated carbon clusters which may have from one to four hydrogen atoms. Complementary measurements performed using Mossbauer spectroscopy allowed it to recognize the crystalline phases of iron compounds observed in the X-ray diffraction patterns. (c) 2005 Elsevier B.V. All rights reserved.

  94. Jartych, E. Calka, A. Smolira, A. Michalak, L., Hydrogen-induced phase transformations in nanostructured graphite made by controlled ball milling, Vacuum, 78(2-4), 2005, 347-351

    Abstract:
    The laser desorption time of flight mass spectrometry and X-ray diffraction methods were used for characterization of phase transformations induced in graphite during controlled reactive mechanical milling under hydrogen atmosphere. During milling for 100 h the crystalline structure of the graphite transformed to nanostructure and some unrecognized crystalline phases. The mass spectrometry method revealed a variety of carbon clusters as well as exotic hydrocarbon molecules in which hydrogen may exist as an atom or a molecule. (c) 2005 Elsevier Ltd. All rights reserved.

  95. Smolira, A. Ptasinska, S. Smolira, M. Michalak, L., Matrix-assisted laser desorption/ionization detection of hemoglobin from long-stored samples of human blood, Vacuum, 78(2-4), 2005, 655-660

    Abstract:
    The effect of blood-storing conditions on the detection of hemoglobin from the whole human blood by the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) method is described. These conditions are the consistence of the blood sample, time and temperature of blood storing. alpha-Cyano-4- hydroxycinnamic acid was used as a desorption matrix for this work. (c) 2005 Elsevier Ltd. All rights reserved.

  96. Dabek, J., Formation of ammonia clusters in a free molecular jet of binary mixtures, Acta Physica Polonica A, 106(4), 2004, 453-466

    Abstract:
    The formation of small ammonia clusters is investigated experimentally with a supersonic free molecular jet of NH3-X binary mixtures (X = Ar, He, N-2), with a special attention paid to the effect of second species X on the cluster formation. The ion currents of protonated ammonia clusters (NH3)(n)H+ (n = 2-6) were measured with a combined cluster source system and a double focussing sector field mass spectrometer. Experiments were made both by changing the species concentration at a constant total pressure and by changing the total pressure with a constant composition of each mixture. The NH3 mole fraction in the tested gas mixtures ranges from 10 to 100% (pure ammonia). It is observed that the formation process of ammonia clusters strongly depends on the nature of the carrier gas and its percentage in the gas mixture. The most likely explanation seems to depend on the unique properties of the free jets; the thermal anisotropy, the spatial cooling, and the mass separation effects.

  97. Feil, S. Gluch, K. Matt-Leubner, S. Scheier, P. Limtrakul, J. Probst, M. Deutsch, H. Becker, K. Stamatovic, A. Mark, T. D., Partial cross sections for positive and negative ion formation following electron impact on uracil, Journal of Physics B-Atomic Molecular and Optical Physics, 37(15), 2004, 3013-3020

    Abstract:
    We report absolute partial cross sections for the formation of selected positive and negative ions resulting from electron interactions with uracil. Absolute calibration of the measured partial cross sections for the formation of the three most intense positive ions, the parent C4H4N2O2+ ion and the C3H3NO+ and OCN+ fragment ions, was achieved by normalization of the total single uracil ionization cross section (obtained as the sum of all measured partial single ionization cross sections) to a calculated cross section based on the semi-classical Deutsch-Mark formalism at 100 eV. Subsequently, we used the OCN+ cross section in conjunction with the known sensitivity ratio for positive and negative ion detection in our apparatus (obtained from the well-known cross sections for SF4+ and SF4- formation from SF6) to determine the dissociative attachment cross section for OCN- formation from uracil. This cross section was found to be roughly an order of magnitude smaller, about 5 x 10(-22) m(2) at 6.5 eV, compared to our previously reported preliminary value. We attribute this discrepancy to the difficult determination of the uracil target density in the earlier work. Using a reliably calculated cross section for normalization purposes avoids this complication.

  98. Gluch, K. Matt-Leubner, S. Echt, O. Concina, B. Scheier, P. Mark, T. D., High-resolution kinetic energy release distributions and dissociation energies for fullerene ions C-n(+), 42 <= n <= 90, Journal of Chemical Physics, 121(5), 2004, 2137-2143

    Abstract:
    We have measured the kinetic energy released in the unimolecular dissociation of fullerene ions, C-n(+)-->C-n- 2(+)+C-2, for sizes 42less than or equal tonless than or equal to90. A three-sector-field mass spectrometer equipped with two electric sectors has been used in order to ensure that contributions from isotopomers of different masses do not distort the experimental kinetic energy release distributions. We apply the concept of microcanonical temperature to derive from these data the dissociation energies of fullerene cations. They are converted to dissociation energies of neutral fullerenes with help of published adiabatic ionization energies. The results are compared with literature values. (C) 2004 American Institute of Physics.

  99. Gluch, K. Matt-Leubner, S. Echt, O. Deng, R. Andersen, J. U. Scheier, P. Mark, T. D., On the kinetic energy release distribution for C-2 evaporation from fullerene ions, Chemical Physics Letters, 385(5-6), 2004, 449-455

    Abstract:
    We present a critical evaluation of the kinetic energy released in the unimolecular dissociation of C-60(+), C-58(+), and C- 56(+). High-quality kinetic energy release distributions (KERD) have been recorded in a three-sector-field mass spectrometer that is equipped with two electric sectors. Systematic errors arising from assumptions about the shape of the KERD are explored by a combination of experiments and simulations; an alternative to the 'model-free approach' is suggested. For decay of C-60(+), an average KER of 394 +/- 14 meV is obtained. Surprisingly, the experimental KER distributions are virtually indistinguishable from the one expected for a pure Langevin- type interaction. (C) 2004 Published by Elsevier B.V.

  100. Gluch, K. Matt-Leubner, S. Michalak, L. Echt, O. Stamatovic, A. Scheier, P. Mark, T. D., High resolution measurements of kinetic energy release distributions of neon, argon, and krypton cluster ions using a three sector field mass spectrometer, Journal of Chemical Physics, 120(6), 2004, 2686-2692

    Abstract:
    Using a newly constructed three sector field mass spectrometer (resulting in a BE1E2 field configuration) we have measured the kinetic energy release distributions of neon, argon, and krypton cluster ions. In the present study we used the first two sectors, B and E1, constituting a high resolution mass spectrometer, to select the parent ions in terms of mass, charge, and energy, and studied the decay of those ions in the third field free region. Due to the improved mass resolution we were able to extend earlier studies carried out with a two sector field machine, where an upper size limit arose from the fact that several isotopomers contribute to a decaying parent ion beam when the cluster size exceeds a certain value. Furthermore we developed a new data analysis. It allows us to model also fragment ion peaks that are a superposition of different decay reactions and thus we can determine the average kinetic energy release for all decay reactions of a given cluster ion. In a further step we used these results to determine the binding energies of cluster ions Rg(n) (ngreater than or equal to10) by applying finite heat bath theory. The smaller sizes have not been included in this analysis, because the validity of finite heat bath theory becomes questionable below napproximate to10. The present average kinetic energy releases and binding energies are compared with other experiments and various calculations. (C) 2004 American Institute of Physics.

  101. Halas, S. Chlebowski, R., Unique siderite occurrence in Baltic Sea: a clue to siderite- water oxygen isotope fractionation at low temperatures, Geological Quarterly, 48(4), 2004, 317-322

    Abstract:
    Recently formed siderite (between 1785 and 1996) at the bottom of South Baltic Sea was investigated by thin section petrography, XRD, electron microprobe (determination of major cation content) and mass spectrometry (delta(15)C and delta(18)O analysis). The siderite was interpreted as having formed from metallic iron partly protected from free oxygen access by wood tar with delta(13)C = -24parts per thousand and from biogenic CO, produced from this organic matter. Inasmuch as the siderite has highly positive delta(13)C values ranging from 8.05 to 15.41parts per thousand, we deduced that extremely isotopically heavy CO2 was generated in the process of biogenic decomposition of the organic matter. It was found that the delta(18)O values of siderite (26.58 to 27.74parts per thousand vs. VSMOW) fit very well to the recalculated curve of Becker (1971) 10(3) In alpha = 3.059 10(6)/T-2 - 4.53 and to published extrapolated experimental data.

  102. Halas, S. Szaran, J., Use of Cu2O-NaPO3 mixtures for SO2 extraction from BaSO4 for sulfur isotope analysis, Isotopes in Environmental and Health Studies, 40(3), 2004, 229-231

  103. Pawelczyk, S. Pazdur, A. Halas, S., Stable carbon isotopic composition of tree rings from a pine tree from Augustow Wilderness, Poland, as a temperature and local environment conditions indicator, Isotopes in Environmental and Health Studies, 40(2), 2004, 145-154

    Abstract:
    Tree rings can be used as archives of climatic and environmental data with annual resolution. Tree rings widths, maximum late wood density and other parameters as stable composition in tree rings can be used for the reconstruction of past climatic and environmental changes. Stable carbon isotope ratios in tree rings may provide valuable information on past climatic conditions. C-13/C-12 ratios of plant organic matter can reflect corresponding 13 C/C-12 ratio of atmospheric CO2 during formation of the rings. Investigations of isotopic carbon composition in tree rings from in the ecologically clean the Augustow Wilderness region in the north-eastern part of Poland (22degrees58'E, 53degrees51'N) (nowadays a sanctuary) were undertaken. Series of delta(13)C in alpha-cellulose and in wholewood were acquired. Those measurements constituted a part of more complex investigations of carbon isotope composition in tree rings including the measurements of radiocarbon concentration and tree ring widths. This article presents preliminary results. It is argued that contrary to the tree ring widths and delta(13)C in wholewood that do not reveal significant correlation with temperature, the variation of delta(13)C in the latewood alpha-cellulose is correlated with combined July and August temperatures.

  104. Halas, S. Durakiewicz, T. Mackiewicz, P., Temperature-dependent work function shifts of hydrogenated/deuteriated palladium: a new theoretical explanation, Surface Science, 555(1-3), 2004, 43-50

    Abstract:
    We explain the phenomena of work function (WF) variations of polycrystalline palladium film due to adsorption and absorption of hydrogen. A small increase of the WF observed at temperatures above 120 K is an indication of a spontaneous formation of H- ions at the surface, subsequently dissociating to electrons and neutral atoms which completely desorb at temperatures above 400 K. A large lowering of the WF at low temperatures (about 2 eV at 78 K) is associated with the formation of PdH. This process is treated quantitatively in the frame-work of the metallic plasma model. The mechanism of the isotope effect on the lowering of the WF is explained by the vibrational frequency difference of H and D atoms confined in the palladium lattice. (C) 2004 Elsevier B.V. All rights reserved.

  105. Halas, S. Mackiewicz, P. Durakiewicz, T., Switching regulator of filament temperature for thermal ionization sources, Vacuum, 73(2), 2004, 291-295

    Abstract:
    The presented circuit is a 4-wire stabilizer of the average voltage on the filament. It has enhanced stability and low power consumption because it works as a switching regulator. The rectangular power pulses supplied to the filament produce small rectangular voltage pulses which are observed by a separate pair of wires connected to the filament ends. These pulses are amplified and converted to the saw-like signal by a low-pass filter. The saw-like signal is connected to the inverting input of the Schmitt trigger, whereas the noninverting input is connected to a reference voltage supplied either from a potentiometer or generated by a computer. The regulator is used in our laboratory for precision potassium analysis by the isotope dilution method. The obtained reproducibility of potassium determination in terms of relative standard uncertainty is 0.5%. (C) 2004 Elsevier Ltd. All rights reserved.

  106. Trembaczowski, A. Szaran, J. Niezgoda, H., Investigating the provenance and seasonal variations in sulphate sulphur and oxygen isotopes of Central Roztocze river water, SE Poland, Water Air and Soil Pollution, 157(1-4), 2004, 65-84

    Abstract:
    The isotope composition of sulphur and oxygen were measured in water collected from the Central Roztocze (SE of Poland) rivers. The research focused mainly on the upper section of the Wieprz River, its confluences and springs and on two confluences of the Tanew River. The results proved that there are two sources of sulphate dissolved in water: the Cretaceous aquifer and soil within the catchment's area. Seasonal variation of the sulphate concentration together with sulphur and oxygen isotope composition was observed. The isotope composition of sulphate varied in water collected at the different locations of the same river. They are similar for sulphates in springs and rivers. The isotope composition of sulphate varied in water collected at the different locations of the same river. The delta(34)S values of sulphates in the Wieprz River are the lowest (negative) in lower part of the river. It shows that the contribution of sulphate from spring water increases downstream. The low sulphate content and high delta(34)S and delta(18)O value in sulphates was found downstream from dams. It may be the result of deficiency of oxygen in mud and the reduction in bacteria activity. The seasonal variations of the oxygen isotope composition in sulphate are significant in sulphates collected from rivers and from springs. They are caused by seasonal variations of the delta(18)O in water stored in the soil. The narrow range of the delta(18)O values for the sulphates extracted from springs at the same time means that the main source of sulphate in spring water are oxidising processes using the same source of oxygen in every location. The high sulphate content combined with the high delta(34)S values of the sulphates in springs suggest, that the sulphates from Cretaceous aquifer were mixed with sulphates dissolved from the soil.

  107. Pelc, A. Sailer, W. Scheier, P. Mark, T. D. Illenberger, E., Fragmentation of propanoic acid by subexcitation electrons, Chemical Physics Letters, 392(4-6), 2004, 465-469

    Abstract:
    Low energy electron attachment to propanoic acid (CH3CH2COOH) leads to a variety of negative fragment ions formed by dissociative electron attachment. The most intense reactions are operative at subexcitation energies (<3 eV) at cross- sections on the 10(-20) m(2) scale. They are due to dehydrogenation from the O site (direct cleavage of the O-H bond), but also more complicated reactions associated with hydrogen transfer and substantial geometric and electronic rearrangement. The present results demonstrate the potential of slow electrons to efficiently decompose organic acids. (C) 2004 Elsevier B.V. All rights reserved.

  108. Gladyszewski, L. Gladyszewski, G. Pienkos, T., Surface ionization of the lanthanides, Vacuum, 74(2), 2004, 301-304

    Abstract:
    The surface ionization of Lanthanides: Ce, Pr, Nd, Sin and Eu, and its fluctuations (noises) have been studied using a double filament ion source in a 90degrees magnetic mass spectrometer. Using the Saha-Langmuir equation there were measured ionization potentials of LnO molecules as the dissociation products of the oxides Ln(2)O(3) (the Ln symbol denotes the arbitrary rare earth elements: Cc, Pr, Nd, Sm, Eu). Ionic desorption energies of LnO molecules were determined using the fluctuation (noise) method. (C) 2004 Elsevier Ltd. All rights reserved.

  109. Ptasinska, S. Dabek, J. Michalak, L., Formation of water dimers in expanding air flows, Vacuum, 70(2-3), 2003, 403-409

    Abstract:
    The production of water dimers by adiabatic gas expansion of the mixture comprised of H2O vapour and air is studied by using an electron impact ion source and a double focusing sector field mass spectrometer. The results of measurements of the generation of (H2O)(2)(+) Cluster ions versus the partial pressure of water vapour at the fixed total pressure of mixture water/air are described. (C) 2003 Elsevier Science Ltd. All rights reserved.

  110. Cicman, P. Gluch, K. Pelc, A. Sailer, W. Matt-Leubner, S. Scheier, P. Matejcik, S. Lukac, P. Robertson, W. D. Compton, R. N. Mark, T. D., Electron impact ionization of CHF2Cl: Unusual ordering of ionization energies for parent and fragment ions, Journal of Chemical Physics, 119(22), 2003, 11704-11711

    Abstract:
    Electron impact ionization of the chlorodifluoromethane molecule is studied using crossed beams of high-resolution electrons and an effusive molecular beam of CHF2Cl. Ionization energies (IEs) for many positive ions from CHF2Cl (CHF2Cl+,CF2Cl+,CHFCl+,CFCl+,CHF2+,CF2+,HCl+,Cl+,CF+,CH+,F+ C+) are determined from a careful examination of the threshold behavior of the ionization cross sections. Reaction pathways for the dissociative ionization products are suggested using known thermodynamic quantities. Surprisingly, it is observed that the ionization threshold for the parent positive ion IE(CHF2Cl+/CHF2Cl)=12.50(+/-0.05) eV lies above that for the fragment ions CHF2+, CHFCl+, and CF+ [IE(CHF2+/CHF2Cl)=12.24(+/-0.03) eV, IE(CHFCl+/CHF2Cl)=12.3(+/- 0.05) eV, and IE(CF+/CHF2Cl)=11.5(+/-0.1) eV]. Experiments using a three sector field BEE mass spectrometer provide evidence for the existence of two states of the parent CHF2Cl+ ion, one exhibiting a short lifetime of about 2 mus and another parent ion state which appears to be stable on the time scale of the experiment (>20 mus) with an IE of 12.50 eV. (C) 2003 American Institute of Physics.

  111. Fedor, J. Parajuli, R. Matt-Leubner, S. Echt, O. Hagelberg, F. Gluch, K. Stamatovic, A. Probst, M. Scheier, P. Mark, T. D., Probing electronic states of Ne-2(+) and Ar-2(+) by measuring kinetic-energy-release distributions, Physical Review Letters, 91(13), 2003, art. no.-133401

    Abstract:
    Dissociative decay of metastable, electronically excited neon and argon dimer ions produces fragment ions with strikingly dissimilar kinetic-energy-release distributions. The distributions have been modeled based on ab initio calculations of potential energy curves. The unusual bimodal distribution observed for dissociation of Ne-2 (+) arises from competition between radiative and nonradiative decay of the long-lived II(1/2)(u) state. For Ar-2 (+), however, electronic predissociation is insignificant.

  112. Halas, S., Ionization potential of large metallic clusters: explanation for the electrostatic paradox, Chemical Physics Letters, 370(1-2), 2003, 300-301

    Abstract:
    The ionization potential of large metallic clusters is IP = WF + alpha(e(2)/4piepsilon(0)R), where WF is the work function, R is the cluster radius, and a is a constant that is equal to 3/8 or 1/2 depending on the method the above formula was derived. This electrostatic paradox was resolved here by using proper values for the work function. In the image charge method WF refers to a plane (denoted as W-x), whereas in the spherical- capacitor approach WF refers to the surface of a grounded metallic ball, which is W-x - (1/8)(e(2)/4piepsilon(0)R). (C) 2003 Elsevier Science B.V. All rights reserved.

  113. Sailer, W. Pelc, A. Limao-Vieira, P. Mason, N. J. Limtrakul, J. Scheier, P. Probst, M. Mark, T. D., Low energy electron attachment to CH3CN, Chemical Physics Letters, 381(1-2), 2003, 216-222

    Abstract:
    Low energy electron attachment cross sections for acetonitrile (CH3CN) are reported in the energy range from about 0 up to 10 eV determined with an energy resolution of 140 meV. Electron attachment is shown to be a purely dissociative process with the production of the five anionic fragments: CH2CN-, CHCN-, CCN-, CN- and CH3- observed in two energy regions, the first between 1 and 4 eV, the second in excess of 6 eV. Quantum chemical and trajectory calculations have been carried out to complement the experimental results. (C) 2003 Elsevier B.V. All rights reserved.

  114. Pelc, A. Sailer, W. Matejcik, S. Scheier, P. Mark, T. D., Dissociative electron attachment to nitroethane: C2H5NO2, Journal of Chemical Physics, 119(15), 2003, 7887-7892

    Abstract:
    Dissociative electron attachment (DEA) to nitroethane (C2H5NO2) in the gas phase is studied using a crossed electron-molecule beams technique. The ion yields for particular fragment ions were measured in the electron energy range from 0 to 9.5 eV with an electron energy resolution of about 120 meV. In contrast to previous studies additional negative ions, i.e., HCN- and NO-, were observed. Measures for the absolute partial cross sections were obtained for the ions using a calibration technique involving a comparison with the known cross section of the 0.8 eV peak in DEA to CCl4. The dominant negative ion product is NO2- with a cross section of approximately 11x10(- 22) m(2) at 0.75 eV. The values of the cross section estimates for the other ions are about sigma(C2H3NO2-)=4x10(-24) m(2) at similar to0 eV, sigma(O-)=5x10(-24) m(2) at 5.7 eV, sigma(OH- )=2x10(-24) m(2) at 5.7 eV, sigma(CN-)=5x10(-25) m(2) at 1.7 eV, sigma(CNO-)=3x10(-25) m(2) at similar to4.5 eV, sigma(HCN- )=2x10(-25) m(2) at similar to4.5 eV and sigma(NO-)=3x10(-25) m(2) at similar to8 eV. (C) 2003 American Institute of Physics.

  115. Cicman, P. Pelc, A. Sailer, W. Matejcik, S. Scheier, P. Mark, T. D., Dissociative electron attachment to CHF2Cl, Chemical Physics Letters, 371(3-4), 2003, 231-237

    Abstract:
    We present results of a crossed electron/molecule beams study concerning dissociative electron attachment (DEA) to CHF2Cl. This study was performed in the electron energy range from about 0-10 eV and at a gas temperature of 300 K. Four fragment negative ions (Cl-, F-, CCIF- and CF2-) were observed. The following partial absolute cross-sections for DEA to CHF2Cl were obtained, 2 x 10(-19) cm(2) at the 1.1 eV resonance for Cl-, 3 x 10(-20) cm(2) at the 3.4 eV resonance for F- ,approximate to 2 x 10(-21) at the 3.0 eV resonance for CCIF- and 3 x 10(-21) at the 8.6 eV resonance for CF2-. Using the cross-section functions obtained, total rate coefficients for DEA to CHF2Cl were calculated giving a value of 9.0 x 10(-13) cm(3)s(-1) at room temperature. Present results are compared with previous data allowing thus to clarify existing discrepancies. (C) 2003 Elsevier Science B.V. All rights reserved.

  116. Pienkos, T. Proszynski, A. Chocyk, D. Gladyszewski, L. Gladyszewski, G., Stress development during evaporation of Cu and Ag on silicon, Microelectronic Engineering, 70(2-4), 2003, 442-446

    Abstract:
    This work presents results of stress measurements during deposition of thin silver and copper films on 100 mum Si substrate. The stress in thin films has been determined by means of an optical system for the measurement of sample's curvature. This system was applied in situ in a high vacuum deposition system. For Ag films the stress occurring during deposition goes from a low compressive value to tensile for thickness less than 30 nm and to compressive above this. For Cu films we observe tensile stress for thickness less 20 nm and above 50 nm. The same general trend of stress evolution with thickness is present in all cases at initial stage. There is the same growth mode for Cu and Ag because of the similar shapes of stress curves for thickness lower than 30 nm The behavior of stress evolution was explained by island nucleation and growth, island coalescence and continuous film growth. The difference in the stress evolution above 30 nm is caused by the fact that silver may be less sensitive than copper to adsorption of impurities. Adsorbed contamination inhibits compressive stress increase generated by grain boundary and defects remaining in the film. (C) 2003 Published by Elsevier B.V.

  117. Pienkos, T. Gladyszewski, L. Proszynski, A. Chocyk, D. Gladyszewski, G. Martin, F. Jaouen, C. Drouet, M. Lamongie, B., Stress development during thin film growth and its modification under ion irradiation, Vacuum, 70(2-3), 2003, 243-248

    Abstract:
    The paper presents the results of average stress measurements during deposition of thin copper and silver films and during ion irradiation of molybdenum thin films. Deposition chamber and ion implanter were equipped with the same optical systems for radius of curvature measurement (scanning technique). The average stress in the 92 nm total thick Cu/Ag/Cu/Ag system on 100 mum Si substrate during deposition at room temperature is reported. Deposition process was intermitted after each material. The non-continuous changes of the stress are interpreted as differences in temperature of the sample in different deposition stages. High residual stresses up to 3 GPa were evidenced in the Mo thin films deposited on Si substrate with RF sputtering. During ion implantation with Kr and Ar ions stress relaxation effect of Mo thin films was observed. Kr ion irradiation of the silicon substrate without a film was additionally performed. After the irradiation (total dose 1.4 x 10(15) ions/cm(2)), the implanted region of the silicon wafer was under compressive stress. A stress maximum was evidenced for a dose of I X 10(14) ions/cm(2). 2003 Elsevier Science Ltd. All rights reserved.

  118. Rajchel, L. Rajchel, J. Szaran, J. Halas, S., Sulfur isotopic composition of H2S and SO42- from mineral springs in the 4 Polish Carpathians, Isotopes in Environmental and Health Studies, 38(4), 2002, 277-284

    Abstract:
    A number of springs in Carpathian Mts. contain dissolved H2S and SO42- in concentrations above 10 mg/dm(3). In this study we have investigated the sulfur isotope composition (delta(34)S) of the dissolved sulfur species in the springs from the flysch area in the Carpathian Mts. along the tectonic dislocation. It is believed that some of these springs may carry a major fraction of dissolved sulfur species of extremely deep sulfur (of mantle origin), which is subjected to SO42--H2S isotope exchange at high temperatures. The original isotopic compositions may be modified by reduction/oxidation at low temperatures and by admixture of sulfur from other sources. In order to distinguish the sulfur of mantle origin we investigated delta(34)S of dissolved sulfide and sulfate and on the basis of known concentrations we calculated delta(34)S of total dissolved sulfur. The isotope fractionation between sulfate and sulfide helped to distinguish the sulfur origin. Evaluating the sulfur isotope exchange, we selected 4 springs which likely have only weakly disturbed sulfur of mantle origin.

  119. Peryt, T. M. Szaran, J. Jasionowski, M. Halas, S. Peryt, D. Poberezhskyy, A. Karoli, S. Wojtowicz, A., S and O isotope composition of the Badenian (Middle Miocene) sulphates in the Carpathian Foredeep, Geologica Carpathica, 53(6), 2002, 391-398

    Abstract:
    A study of 333 samples from eight sulphate sections of the Badenian (Middle Miocene) from the marginal part of the Carpathian Foredeep basin and one section from its central part proved that the isotopic compositions of both oxygen and sulphur show a similar trend of evolution throughout the sections. In some cases, in the lower part of gypsum sections a gradual decrease of delta(34)S and delta(18)O is observed. In turn, the upper part of the section shows fluctuations of quite high amplitude, but within a clearly defined interval. The variation of delta(18)O values in the whole area is similar to that of delta(34)S values although in particular facies the variation ranges are different. Clastic gypsum shows the greatest spread of delta(34)S and delta(18)O values. 39 % of all delta(34)S values and 46.5 % of all delta(18)O values are higher than those characteristic for the marine sulphate values, and these higher values are mostly characteristic for elastic gypsum. Selenitic gypsum shows relatively narrow ranges of delta(34)S and delta(18)O values and hence is especially useful for analyses of depositional conditions. The isotopic composition of Badenian sulphates reflects the marine origin of brines. The recorded great spread of delta(34)S and delta(18)O values in the Badenian sulphates is related to the recycling of previously formed evaporites already during gypsum precipitation in the Carpathian Foredeep basin.

  120. Kovalevych, V. M. Peryt, T. M. Carmona, V. Sydor, D. V. Vovnyuk, S. V. Halas, S., Evolution of Permian seawater: evidence from fluid inclusions in halite, Neues Jahrbuch Fur Mineralogie-Abhandlungen, 178(1), 2002, 27-62

    Abstract:
    The examination of primary fluid inclusions in sedimentary halite from several Permian evaporite basins of East and Central Europe (Asselian and Sakmarian Dnipro-Donets Basin of Ukraine, Sakmarian Dvina-Sukhona Basin of Russia, Kungurian Solikamsk Basin of Russia, Zechstein Basin of Poland and Peri- Baltic Russia) revealed that the brines were of Na-K-Mg-Cl-SO4 (SO4-rich) chemical type. They are characterized by minor content Of SO4 ions, when compared with modem seawater concentrated to the corresponding stage. The lowest SO4 content was recorded in the Kungurian; a higher SO4 content was found in the Asselian and Sakmarian; and the highest content in the Late Permian. The bromine content in halite of the Permian salts of East and Central Europe (mostly 30-160 ppm) correlates with ion concentration in brine inclusions. The marine origin of salt in most of the studied sections is supported by isotopic composition of sulphate sulphur. During salt deposition in every basin, local factors - such as the inflow of surface or subsurface waters, sulphate reduction, and water- rock interaction - have exerted important influences on the K, Mg, and SO4 ion ratios. However, these changes did not lead to the change of the chemical, SO4-rich type that is characteristic for the Permian evaporite basins.

  121. Halas, S. Durakiewicz, T., Temperature dependence of the surface energy of mercury from 0 to 250 degrees C, Journal of Physics-Condensed Matter, 14(47), 2002, L735-L737

    Abstract:
    The surface energy (SE) for mercury was calculated on the basis of the free electron model in which the electron density parameter, r(s), for bulk electrons was calculated from the density of mercury while the electron density parameter for surface electrons, r(ss), was assumed to be higher by a factor that is linearly dependent on temperature. Ideal agreement of calculated SE values with experimental data was attained for the temperatures 0-250 degreesC assuming that r(ss) = r(s) x 1.0021(T/100degreesC).

  122. Han, L. Tanweer, A. Szaran, J. Halas, S., A modified technique for the preparation of SO2 from sulphates and sulphides for sulphur isotope analyses, Isotopes in Environmental and Health Studies, 38(3), 2002, 177-183

    Abstract:
    A modified technique for the conversion of sulphates and sulphides to SO2 with the mixture of V2O5-SiO2 for sulphur isotopic analyses is described. This technique is more suitable for routine analysis of large number of samples. Modification of the reaction vessel and using manifold inlet system allows to analyse up to 24 samples every day. The modified technique assures the complete yield of SO2, consistent oxygen isotope composition of the SO2 gas and reproducibility of delta(34)S measurements being within 0.10parts per thousand. It is observed, however, oxygen in SO2 produced from sulphides differs in delta(18)O with respect to that produced from sulphates.

  123. Halas, S. Durakiewicz, T. Joyce, J. J., Surface energy calculation - metals with 1 and 2 delocalized electrons per atom, Chemical Physics, 278(2-3), 2002, 111-117

    Abstract:
    In this paper we calculate surface energy (SE) of monovalent, divalent and some trivalent metals. For these metals for which SE can be solely expressed by dimensionless Wigner-Seitz density parameter, r(s), of delocalized electrons: SE = C(1)r(s)(-5) + C2r(s)(-3.5) - C(3)r(s)(-4), where constants C- 1, C-2 and C-3 have been calculated on the basis of Sommerfeld's free electron and surface plasma models. Excellent agreement with experimental data was obtained. On the basis of our model SE values for Fr and Ra have been predicted as well. (C) 2002 Published by Elsevier Science B.V.

  124. Kovalevych, V. Peryt, T. M. Beer, W. Geluk, M. Halas, S., Geochemistry of Early Triassic seawater as indicated by study of the Rot halite in the Netherlands, Germany, and Poland, Chemical Geology, 182(2-4), 2002, 549-563

    Abstract:
    Study of three halite sections in the Rot Basin from the eastern Netherlands (Twente-Rijn 382 borehole), central Germany (Mardorf 6 borehole) and western Poland (Osno IG2 borehole) shows that the delta(34)S values in Rot sulphates of studied samples (27.14-31.98parts per thousand) are characteristic of marine sulphates of late Early Triassic. These values fit in the Rot event shift described in the literature. The bromine content in halite is 32-158 ppm. In the Dutch and Polish sections, relics of sedimentary structures-chevron and hopper- are recorded in halite grains. These structures contain fluid inclusions that were analysed using the ultramicrochemical method of Petrichenko (Petrichenko, O.I. 1973. Metody doslidzhennya vkluchen' v mineralakh galogennykh porid. Kiev, Naukova Dumka, 92 pp.). In the German section, no sedimentary halite structures occur. Because the pressure in the inclusions in recrystallized halite is only slightly greater than atmospheric pressure, these inclusions are presumed to be early diagenetic in origin. The analysis of individual brine inclusions, both in sedimentary and diagenetic forms of halite, shows that the Rot brines correspond to the Na-K-Mg-Cl-SO4 (SO4-rich) chemical type, i.e. the same type that characterises modem seawater. However, the Rot brines differ from the composition characteristic of modern concentrated seawater by a decrease in the content of sulphate ion and an increase in the content of potassium ion. On a Janecke diagram, the points of the brine composition during deposition of Rot halite in Poland, Germany and the Netherlands only show a small range. This suggests a stable composition of basinal brines during the deposition of the halite. At the same time, the relative content of sulphate ion in the Lower Triassic Rot Basin was slightly lower than that in Upper Permian evaporite basins, but higher than that in Lower and Middle Permian and Middle and Upper Triassic evaporite basins. The implication is that the content of sulphate ion in seawater was subject to changes in Permian and Triassic times. (C) 2002 Elsevier Science B.V. All rights reserved.

  125. Halas, S. Wojtowicz, A. Nowak, J. Durakiewicz, T., Temperature controller for thermal ionization mass spectrometry, Rapid Communications in Mass Spectrometry, 16(1), 2002, 77-80

    Abstract:
    We describe the use of a simple voltage stabilizer that controls the filament temperature (T-f) in the ion source of a thermal ionization mass spectrometer. The filament voltage (V- f) is measured by means of a separate pair of wires connected inside of the ion source in parallel to the wires supplying power. It has been demonstrated that V-f is directly proportional to T-f in a wide range of filament temperature. The T-f value is solely controlled by the reference voltage (V- r) that can be manually selected from a voltage divider or by means of a computer. Digital signals from the computer in the form of a series of pulses are transmitted opto-electronically and subsequently converted to analog signals. The temperature controller described here was successfully applied for analysis of potassium concentration by the isotope dilution method. Copyright (C) 2001 John Wiley & Sons, Ltd.

  126. Sailer, W. Pelc, A. Matejcik, S. Illenberger, E. Scheier, P. Mark, T. D., Dissociative electron attachment study to nitromethane, Journal of Chemical Physics, 117(17), 2002, 7989-7994

    Abstract:
    Dissociative electron attachment (DEA) to CH3NO2 in the gas phase was studied in the electron energy range from zero up to 10 eV with an energy resolution of 140 meV. For the most intense negative fragments NO2-, O-, OH-, CN-, CNO- estimates for the absolute partial cross sections were obtained for the first time [sigma(NO2)approximate to10(-21) m(2) at 0.62 eV, sigma(O-)approximate to10(-23) m(2) at 5.4 eV, sigma(OH- )approximate to10(-24) m(2) at 4 eV, sigma(CN-)approximate to10(-24) m(2) at 1.7 eV, and sigma(CNO-)approximate to10(-25) m(2) at 4 eV]. In the case of OH-, CN-, and CNO-, ion formation at very low electron energies (approximate to0 eV) has been observed in contrast to previous studies. The formation of OH- and CNO- at these low electron energies is explained in terms of DEA to vibrationally excited molecules. Analyzing measured partial cross sections, the standard enthalpy of formation of the CH3NO (nitroso-methane) and the CNO radical has been estimated, as Delta(f)H(g)(o)(CH3NO)=129+/-30 kJ/mol and Delta(f)H(g)(o)(CNO)=323+/-30 kJ/mol, respectively. (C) 2002 American Institute of Physics.

  127. Pelc, A. Sailer, W. Scheier, P. Probst, M. Mason, N. J. Illenberger, E. Mark, T. D., Dissociative electron attachment to formic acid (HCOOH), Chemical Physics Letters, 361(3-4), 2002, 277-284

    Abstract:
    Dissociative electron attachment to formic acid as a fundamental center in enzymatic activity is studied. A prominent resonance is observed peaking at 1.25 eV which decomposes into the formate anion HCOO- and a hydrogen radical. Resonances at higher energy are associated with O- and OH- formation on a considerably smaller intensity scale. On the basis of high level ab initio calculations, the low energy feature arises from different closely spaced single particle shape resonances with no specific valence character. The HCOO- ion yield carries structure which is tentatively ascribed to vibrational excitation in the formate anion. (C) 2002 Elsevier Science B.V. All rights reserved.

  128. Sailer, W. Drexel, H. Pelc, A. Grill, V. Mason, N. J. Illenberger, E. Skalny, J. D. Mikoviny, T. Scheier, P. Mark, T. D., Low energy electron attachment to SF5CF3, Chemical Physics Letters, 351(1-2), 2002, 71-78

    Abstract:
    Low energy electron attachment to the potent greenhouse gas SF5CF3 is studied at high energy resolution by means of mass spectrometric detection of the product anions. A large dissociative electron attachment (DA) cross-section forming SF5- + CF3 is observed within a very narrow energy range close to zero eV. In addition, comparatively weak resonances are observed near 1 eV yielding the fragment ions CF3- and F-. Some implications for the atmospheric lifetime of SF5CF3 and hence its global warming potential (GWP) are considered. (C) 2002 Elsevier Science B.V. All rights reserved.

  129. Pienkos, T. Gladyszewski, L. Chocyk, D. Proszynski, A. Gladyszewski, G. Martin, F. Jaouen, C., Measurements of stress during ion irradiation, Optica Applicata, 32(3), 2002, 421-424

    Abstract:
    The exemplary results obtained with a simple optical set-up for the measurement of curvature radius during ion implantation are presented. The Kr ion irradiation was performed for silicon substrate without a film. After the irradiation the implanted region of silicon was under compressive stress. Maximum of the stress was evidenced for a dose of 1X10(14) ions/cm(2). The optical set-up is very flexible and may cooperate with various apparatus.

  130. Trembaczowski, A. Swieca, A., Sulphur and oxygen isotopic composition of sulphates in springs feeding the Wieprz River and other springs of Lublin Upland and Roztocze, Isotopes in Environmental and Health Studies, 38(4), 2002, 285-306

    Abstract:
    Springs on Roztocze and Lublin Upland have been studied. Isotopic data are compared with data of chemical analyses. The results of studies allow us to distinguish five types of groundwaters. The differentiation is based upon different lithology; opokas, gaizes, sandy-silty-clay deposits, sands with shell sandstones, marly opokas, marly limestones' and soft limestones of chalk type. A correlation can be observed between delta(34)S and the concentration of Ca or Mg ions also a correlation between HCO3- ion concentration and delta(18)O in sulphates. Probably these correlations are the result of some simultaneous processes, which occur in groundwater. The seasonal variations of the isotopic composition and sulphate concentration were observed in four springs feeding the upper Wieprz. The variations were simultaneous and often similar in these springs. Probably, these variations are caused by the admixture of sulphates coming from shallow water layers (or leached from soil); however the variations of the groundwater level may also change chemical and isotopic composition in groundwater.

  131. Vokal, B. Szaran, J. Trembaczowski, A. Dolenec, T., The isotopic composition of sulfates in rivers the Ljubljanica and the Sava in Slovenia, Geochimica Et Cosmochimica Acta, 66(15A), 2002, A809-A809

  132. Dabek, J. Michalak, L., Size-dependent fragmentation of carbon dioxide clusters, Vacuum, 63(4), 2001, 555-560

    Abstract:
    A combined nozzle cluster source system and double focusing sector field mass spectrometer were used to study the fragmentation of (CO2)(n)(+) cluster ions (n < 22). The ions were generated by electron impact. The relative intensities of the fragment ions are found to be dependent on cluster size. The high abundance of ions (CO2)(4,5)X+ and (CO2)(15,16)X+ (X = O, CO, O-2) indicate pronounced stabilities of these cluster ions, (C) 2001 Elsevier Science Ltd. All rights reserved.

  133. Bajuk, A. Gluch, K. Michalak, L., Effect of impurities on the matrix-assisted laser desorption/ionization mass spectra of insulin, Rapid Communications in Mass Spectrometry, 15(24), 2001, 2383-2386

    Abstract:
    The effect of impurity (sodium sulfate Na2SO4; copper sulfate CuSO4; potassium ferrocyanide K4Fe(CN)(6); and triammonium citrate (NH4)(3)C6H5O7) concentration on the positive matrix- assisted laser desorption/ionization time-of-flight (MALDI-TOF) spectra of insulin is described. 2,5-Dihydroxybenzoic acid was used as a desorption matrix. The estimated maximum concentrations of tested salts for which no insulin signal was observed were determined. Copyright (C) 2001 John Wiley & Sons, Ltd.

  134. Pawlyta, J. Pazdur, A. Goslar, T. Halas, S., Influence of the bomb-produced C-14 on the radiocarbon concentration in the youngest sediments of Lake Gosciaz, Central Poland, Radiocarbon, 43(2B), 2001, 831-841

    Abstract:
    This work is a study of changes of the radiocarbon concentration in the youngest part of Lake Gosciaz sediments in the calendar time scale during the last 150 years. This period includes the time of the nuclear weapons tests performed in the upper atmosphere in the 1950s and the 1960s, which caused large release of C-14 and Cs-137 into the environment. On the basis of this study, the isotope dilution factor for C-14 and the exchange time of carbon between the atmosphere and Lake Gosciaz was estimated. The chronology of the upper part of the sediments was constructed using many interdisciplinary investigations. Among them, measurements of Cs-137 in the sediment were used. An unexpected discrepancy between the previously constructed time scale and that suggested by Cs-137 is observed in one of the cases.

  135. Halas, S. Szaran, J., Improved thermal decomposition of sulfates to SO2 and mass spectrometric determination of delta S-34 of IAEA SO-5, IAEA SO-6 and NBS-127 sulfate standards, Rapid Communications in Mass Spectrometry, 15(17), 2001, 1618-1620

    Abstract:
    We describe a significant improvement to our low-temperature thermal decomposition of sulfates to SO2 for isotopic analysis (Halas S, Szaran J. Anal. Chem. 1999; 71: 3254) that has led to better reproducibility and efficiency of measurements. In the present approach we use a mixture of two reagents, NaPO3 + V2O5, mixed in a weight ratio of 3:5. The addition of V2O5 prevents overboiling of NaPO3 at temperatures, T, increased to 800 degreesC. Using this modified method we obtained the following delta S-34 values (in parts per thousand): +21.17 +/- 0.12 for NBS-127, +0.15 +/- 0.06 for IAEA SO-5, and -34.12 +/- 0.11 for IAEA SO-6. Copyright (C) 2001 John Wiley & Sons, Ltd.

  136. Durakiewicz, T. Halas, S. Arko, A. Joyce, J. J. Moore, D. P., Electronic work-function calculations of polycrystalline metal surfaces revisited, Physical Review B, 6404(4), 2001, art. no.-045101

    Abstract:
    A brief comparison of methods used to calculate the electronic work function of polycrystalline metal surfaces is presented. We show that the ab initio methods are unable to give values in acceptable agreement with experiments, whereas simple models based on the free-electron gas approach and classical electrodynamics work well, even in complicated electronic systems like transition metals. lanthanides, or actinides. This observation is made on the basis of previously published computations by the authors and new results for lanthanides and actinides. Surface valence transitions from trivalent to divalent for Sm and Tm are indicated. Heavy actinides work functions are presented. The results are compared with available experimental and theoretical values, and an attempt to address the reasons for ab initio failure is undertaken on the basis of a concept of quantum decoherence.

  137. Durakiewicz, T. Halas, S., Calculation of ionization potential of small yttrium and lanthanide metal clusters, Chemical Physics Letters, 341(1-2), 2001, 195-200

    Abstract:
    Our analytic formula for ionization potential (IP) of a metal cluster of given radius, R, is adapted to small size clusters with number of atoms n < 40. The radius is defined as the distance between gravity center and the most remote atom surface. R was either calculated or determined experimentally with relative uncertainty of 3%. We have found that R(n) significantly fluctuates around 1.30 n(1/3) for n < 40. The calculated IP values for Y-n and Ce-n small clusters indicate the valence transition from Z = 3 to Z = 2 at n = 6 and 3, respectively, whereas Z = 3 may be considered for Pr-5 and perhaps for Pr-6 <(c)> 2001 Published by Elsevier Science B.V.

  138. Durakiewicz, T. Arko, A. J. Joyce, J. J. Moore, D. P. Halas, S., Thermal work function shifts for polycrystalline metal surfaces, Surface Science, 478(1-2), 2001, 72-82

    Abstract:
    A new approach is presented fnr the calculation of the thermal shifts of the work functions of polycrystalline metal surfaces by including the thermal expansion of the metal into the election density parameter as il ell as Fermi energy. Calculations of d phi /dT as a function of temperature are performed for 74 elements, encompassing a total of 103 cases of various temperature ranges, phases and (in a few cases) orientations. II is shown that for a majority of metals d phi /dT is not a constant over a broad temperature range. Comparison of theoretical and experimental values indicates that the thermal lattice vibrations do not influence d phi :dT significantly. Our results would suggest that the use of a Kelvin probe to measure the thermal variation of phi may be problematic. (C) 2001 Elsevier Science B.V. All rights reserved.

  139. Pluta, I. Trembaczowski, A., Changes of the chemical composition of discharged coal mine water in the Rontok Pond, Upper Silesia, Poland, Environmental Geology, 40(4-5), 2001, 454-457

    Abstract:
    The natural process of sulphate reduction takes place in the Rontok Pond. During the reduction the concentration of sulphate in the pond water decreases. The changes of delta S-34 in the pond water are typital for bacterial reduction. The reduction process in the Rontok Pond causes dissolution of barium and the radium from the pond sediments into the water. Concentrations of barium and Ra-226 in the discharged water from the Silesia Coal Mine are lower than in water flowing out of the Rontok Pond into the Vistula River. The opposite trend is observed for iron and also Zn, Co, Ni, Mn, Al and Cu because of the precipitation of ferric hydroxide in the stream. The reduction process, which causes dissolution of barium and radium in water, can explain the release of these elements into the Vistula River. The dissolution of toxic elements can be reduced by the precipitation of nontoxic deposits on the sediment of Rontok Pond.

  140. Halas, S. Szaran, J. Niezgoda, H., Reply to the Comment by M. P. Verma on "Experimental determination of carbon isotope equilibrium fractionation between dissolved carbonate and carbon dioxide", Geochimica Et Cosmochimica Acta, 64(3), 2000, 575-577

  141. Pelc, A. Michalak, L., Electron ionization study of ammonia microclusters, Rapid Communications in Mass Spectrometry, 14(16), 2000, 1455-1461

    Abstract:
    An electron impact ion source on a double focusing sector field mass spectrometer was used to investigate ammonia micro- clusters produced by the adiabatic free jet expansion of ammonia gas. The appearance energies for [NH3](n)(+), n less than or equal to 9, ions have been determined. Results of measurements of appearance pressures of selected clusters are described for a range of operating conditions. An empirical formula describing the ammonia clusters production is proposed. Copyright (C) 2000 John Wiley & Sons, Ltd.

  142. Michalak, L. Pelc, A., Homologous micro-clusters of carbon disulphide, Vacuum, 57(1), 2000, 61-70

    Abstract:
    Mass spectrometric investigations of homologous micro-clusters (n less than or equal to 6) of carbon disulphide are studied by using an electron impact ion source and a double focusing sector field mass spectrometer. Clusters are produced by adiabatic gas expansion of mixture of CS, vapour and Ar. The appearance potentials for ions (CS2)(n)S+, (CS2)(n)CS+, (CS2)(n)S-2(+) (n = 1 and 2), CS2C+ and (CS2)(3)S+ are determined. The temperature dependences of selected clusters are also presented. (C) 2000 Elsevier Science Ltd. All rights reserved.

  143. Pelc, A. Michalak, L., Production of carbon disulphide dimers by an adiabatic gas expansion method, International Journal of Mass Spectrometry, 194(1), 2000, 85-91

    Abstract:
    The production of carbon disulphide dimers by adiabatic gas expansion of a mixture comprised of CS2 vapour and Ar is studied by using an electron impact ion source and a double focusing sector field mass spectrometer. Results of measurements of the generation of (CS2)(2)(+) cluster ions versus the stagnation pressure (0-160 kPa) at several stagnation temperatures (267-300 K) are described. An empirical formula describing the carbon disulphide dimer production is proposed. (C) 2000 Elsevier Science B.V.

  144. Pienkos, T. Gladyszewski, L. Chocyk, D. Gladyszewski, G., Stress relaxation effects in Ag/Pd superlattices at initial stages of ion beam mixing, Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, 288(2), 2000, 266-269

    Abstract:
    Initial stages of the ion beam mixing process in Ag/Pd multilayers are analyzed using X-ray diffraction. The interface spread caused by ion irradiation is reflected in changes in the relative intensities of satellite superlattice peaks. Diffraction profiles measured after ion irradiation are interpreted using computer programs based on a Monte Carlo simulation. The thickness of mixed interface regions and interplanar distances of both components of multilayer are determined for each stage of ion irradiation. The determined mixing parameter is independent of the multilayer period and of the relative concentrations of components. A stress relaxation effect is observed for low ion doses. (C) 2000 Published by Elsevier Science S.A.

  145. Dabek, J. Michalak, L., Study of CO2 clusters by mass spectrometry, Nukleonika, 44(2), 1999, 293-297

    Abstract:
    The beams of (CO2)(n) cluster ions (n = 2-18) are studied by the adiabatic nozzle expansion of CO2 and subsequent ionisation by the electron impact. They are analysed in a double focussed sector field mass spectrometer. In the case of 70 eV electron energy four homologous series of ions can be identified in the mass spectrum.

  146. Dudek, K. Bukowski, K. Wojtowicz, A. Durakiewicz, T. Halas, S., Ar/Ar dating of hornblende samples from Carpathian igneous rocks, Geologica Carpathica, 50(), 1999, 93-94

  147. Halas, S. Szaran, J., Low-temperature thermal decomposition of sulfates to SO2 for on-line S-34/S-32 analysis, Analytical Chemistry, 71(15), 1999, 3254-3257

    Abstract:
    We describe a fast, inexpensive, and safe method of direct SO2 extraction from BaSO4 for sulfur isotopic analysis by mass spectrometry. Only two reagents are used: (1) pure NaPO3, which is mixed with BaSO4 sample, and (2) Cu foil, from which reaction boats are manufactured. The extraction precedes in the Cu boat placed into a quartz tube connected to a vacuum line. The boat is heated to 650-700 degrees C while pure SO2 produced is collected in a "cold finger". Reaction is complete in 7-10 min. We have proven by means of O-18-enriched BaSO4 specimens that the oxygen isotopic composition of the SO2 is totally controlled by O-18 content in NaPO3, when the weight ratio of the reagent to sample exceeds 6:1. The method described can be used for "on-line" SO2 preparation for isotopic analysis.

  148. Durakiewicz, T. Halas, S., Thermal relaxation of hot filaments, Journal of Vacuum Science & Technology a-Vacuum Surfaces and Films, 17(3), 1999, 1071-1074

    Abstract:
    A stretched exponential function is used to fit the cooling curve of a tungsten filament. Fitting parameters are given for a set of tungsten filaments varying from 10 to 100 mm in length and from 0.05 to 1 mm in diameter. The instantaneous time constant of cooling and its dependence on temperature and position along the filament are discussed. (C) 1999 American Vacuum Society. [S0734-2101(99)00103-7].

  149. Halas, S. Durakiewicz, T., Apparatus for DSC analysis of milligram samples, Journal of Thermal Analysis and Calorimetry, 55(2), 1999, 565-568

    Abstract:
    A novel DSC apparatus is based on resistance thermometers comprising two legs of a modified resistance bridge (Halas- Kaminski bridge) in which one resistor can be energized from an external source. Two metal spirals installed in a regulated oven are used as thermometers and sample holders. Two scans for 20 mg of NH4NO3 demonstrate the high sensitivity of this method.

  150. Pelc, A. Michalak, L., Electron impact study of argon clusters, Nukleonika, 44(2), 1999, 317-327

    Abstract:
    The production of argon clusters Ar-n, n less than or equal to 21, by adiabatic gas expansion of Ar is studied by using an electron impact ion source and a double focusing sector field mass spectrometer. Results of measurements of appearance pressures of selected clusters are described for a range of operating conditions. The appearance pressures of observed clusters showed a slowly increasing dependence on cluster size.

  151. Pelc, A. Michalak, L., Electron impact study of carbon disulphide micro-clusters, Vacuum, 52(3), 1999, 261-268

    Abstract:
    The production of carbon disulphide micro-clusters (CS2)(n) n less than or equal to 11, by adiabatic gas expansion of mixture of CS2 vapour and Ar is studied by using an electron impact ion source and a double focusing sector field mass spectrometer. The appearance potentials for clusters n less than or equal to 9 decreased as n increased but was not a simple function of 1/n. The appearance pressures of observed clusters showed a slowly increasing dependence on cluster size. Results of measurements of appearance potentials and appearance pressures of selected clusters are described for a range of operating conditions. (C) 1999 Elsevier Science Ltd. All rights reserved.

  152. Halas, S. Durakiewicz, T., Filament temperature stabilizer for a thermal ionization mass spectrometer, International Journal of Mass Spectrometry, 181(), 1998, 167-171

    Abstract:
    A major enhancement in temperature stabilization of a filament has recently been achieved by means of the Halas-Kaminski bridge, in which the reference resistance of one leg is directly proportional to the filament temperature. In this article we describe a novel version of this type of electronic circuit which feeds de power voltage to the filament via a switching transistor. The switching frequency is regulated by means of a triangular waveform generator incorporated into the system. The duration of the heating peak (square wave) is automatically adjusted properly once at each break between two subsequently appearing heating peaks, which is the interval when the bridge imbalance signal is measured. At the end of each break the bridge imbalance signal is kept on the output of the sample-and-hold amplifier. This signal compared with the generator output voltage provides the square wave for the switching transistor. The application of this circuit for a thermal ionization mass spectrometry is simple and straightforward. The filament temperature is set by two decade low-ohm resistors. Long-term variance of the ion current is approximately 5 times lower than that obtained by use of a commercial voltage stabilizer for the filament supply. It is shown theoretically that stabilization of the filament resistance results in the lowest possible variance of temperature. (Int J Mass Spectrom 181 (1998) 167-171) (C) 1998 Elsevier Science B.V.

  153. Halas, S. Durakiewicz, T., Work functions of elements expressed in terms of the Fermi energy and the density of free electrons, Journal of Physics-Condensed Matter, 10(48), 1998, 10815-10826

    Abstract:
    On the basis of Brodie's definition of the work function and the length of spontaneous polarization of plasma, the following new formula for calculation of the work functions of elements has been derived: phi/eV = 43.46 alpha r(s)(-3/2) (E-F/eV)(- 1/2), where r(s) is the electron density parameter expressed in units of the Bohr radius, EF is the Fermi energy and alpha is an empirical constant (alpha = 0.86 for the alkali metals, Ca, Sr, Pa Ra and Tl, whereas alpha = 1.00 for the remaining elements). The density parameter was calculated from the atomic mass, the bulk density of the element and the assessed number of free electrons per atom which is equal to the nominal valence of the element or, in the case of transition metals, close to this number (within +/-0.5). The values obtained by using the above formula are in excellent agreement with experimental data for pure-metal polycrystalline surfaces, within 5% in most cases. A table with the work functions and with complete input data for most of the elements is presented.

  154. Durakiewicz, T. Halas, S., Cooling of an incandescent filament by thermionic emission, International Journal of Mass Spectrometry, 177(2-3), 1998, 155-161

    Abstract:
    The lowering of temperature of incandescent tungsten filaments by thermionic emission was investigated both theoretically and experimentally. The effect is significant at tungsten filament temperatures above 2300 K. The influence of this effect on lowering the electron emission current density as well as its significance in mass spectrometry and electron beam evaporation are briefly discussed. Neglecting the effect resulted in lowering of experimentally determined work function to 4.10 eV instead of 4.57 eV for tungsten. Methods of calculation of corrected filament temperature and saturation emission current are presented. (Int J Mass Spectrom 177 (1998) 155-161) (C) 1998 Elsevier Science B.V.

  155. Halas, S. Szaran, J. Niezgoda, H., Reply to the comment by P.M. Lesniak on "Experimental determination of carbon isotope equilibrium fractionation between dissolved carbonate and carbon dioxide", Geochimica Et Cosmochimica Acta, 62(12), 1998, 2198-2198

  156. Halas, S. Durakiewicz, T., Temperature distribution along a metal filament heated in vacuum by DC current, Vacuum, 49(4), 1998, 331-336

    Abstract:
    A numerical method is presented for the solution of the differential equation for temperature distribution along a filament heated electrically and subjected to heat loss by radiation according to the Stefan-Boltzmann law and heat conductivity (effect of leads). The solution can be precisely found if the temperature calculation is started from the filament centre. In this way reliable temperature and resistance distributions are obtained at division of the whole length into a few hundred pieces. The calculated results are compared with Langmuir's experimental data, which demonstrates the great usefulness and reliability of this approach. (C) 1998 Elsevier Science Ltd. All rights reserved.

  157. Durakiewicz, T. Halas, S., Computation of time-dependent temperature distribution along a filament heated in vacuo by electric pulses, Journal of Vacuum Science & Technology a-Vacuum Surfaces and Films, 16(1), 1998, 194-199

    Abstract:
    Numerical solution of the second-order partial differential equation describing the evolution of temperature of a tungsten filament in time allows the simulation of some effects that occur in the case of heating thp filament by a series of pulses. Namely, the phenomena investigated are (1) phase shifts between heating current and filament temperature, (2) amplitude of temperature modulation due to variation of supply voltage and (3) the temperature dependence of the time constant of temperature changes. The method presented here may be used for any filament working in vacuo. It may be applied in mass spectrometry, vacuum measurements, thin films deposition by hot filaments and other applications. (C) 1998 American Vacuum Society.

  158. Halas, S. Trembaczowski, A. Soltyk, W., Application of isotopic analyses to study the influence of exploitation of brown coal on the pollution of groundwater, Isotopes in Environmental and Health Studies, 33(3), 1997, 315-326

    Abstract:
    This research deals with pollution impact on natural water resources in the industrial area of Belchatow, central Poland, where a large brown coal deposit is exploited and the coal is burned in an electric power plant. To trace the sources of groundwater pollutants the stable isotope analysis of oxygen and sulfur in sulfates was applied. The mass-spectrometric analysis was performed on SO42- samples from numerous wells and piezometres in the excavation area. By repetitive sampling performed in November 1994, May 1995 and December 1996 significant changes of SO42- concentration and sulfur and oxygen isotopic ratios in several sites were recorded. The interpretation of isotope ratios allowed us to recognize three groups of sulfates: (1) from the leaching of Permian salt dome; (2) produced by the leaching of soluble sulfates from an ash pool and (3) produced by oxidation of natural sulfides in water-bearing rocks.

  159. Halas, S. Szaran, J. Niezgoda, H., Experimental determination of carbon isotope equilibrium fractionation between dissolved carbonate and carbon dioxide, Geochimica Et Cosmochimica Acta, 61(13), 1997, 2691-2695

    Abstract:
    By mixing aliquots of pure Na2CO3 and CO2 solutions with precisely known molal fractions of CO3=, HCO3-, and dissolved CO2 were prepared. The apparent fractionation factor between gaseous CO2 and total carbon in the solution was determined mass spectrometrically from which the CO3= - CO2 fractionation factor was calculated taking into account the known fraction of HCO3- and respective isotope fractionation. Although the measurements have been made for a rather narrow temperature range, from 4 to 80 degrees C, a theoretical curve was fitted through the experimental points, and thereby, the isotopic partition function ratio of (CO3=)-C-13 and (CO3=)-C-12 molecules has been obtained for an extended temperature range. The results obtained for CO3=-CO2 isotope fractionation are significantly lower than those for HCO3--CO2 exchange (with 10(3)(alpha - 1) = 5.0 +/- 0.2 at 25 degrees C and cross-over point at about 63 degrees C). Copyright (C) 1997 Elsevier Science Ltd.

  160. Dudziak, A. Halas, S., Diurnal cycle of carbon isotope ratio in soil CO2 in various ecosystems, Plant and Soil, 183(2), 1996, 291-299

    Abstract:
    Our investigations of diurnal variations of the C-13/C-12 ratio and CO2 content in soil air were carried out in three environments during periods of high biosphere activity. It has been observed that diurnal variation of CO2 concentration is negatively correlated delta(13)C. Particularly great variations occurred at shallow soil depths (10-30 cm) when the plant cover activity was high while the soil temperature was rather low. Under such conditions the delta(13)C variations had the magnitude of 4 parts per thousand, while the CO2 concentration varied more than doubly. The maximum of the C-13/C-12 ratio and the minimum of the CO2 concentration in a cultivated field with winter wheat took place in the afternoon, whereas in deciduous forest similar patterns were observed at dawn. In these cases soil temperatures at 10 cm depths varied less than 2 degrees C. Hence, under wheat the variation in root respiration rate seem to be the main reason of the recorded varations. In an uncultivated grass-field during the hottest period in summer we did not measure any distinct variations of CO2 properties in spite of the fact that soil temperature varied up to 5 degrees C. This might be due to dominant microbial respiration at the high soil temperature, which exceeded 20 degrees C.

  161. Halas, S. Jasinska, B., Platinized magnesium as reducing agent for hydrogen isotope analysis, Isotopes in Environmental and Health Studies, 32(1), 1996, 105-109

    Abstract:
    Platinized magnesium has recently been proposed as a new reducing agent for the conversion of small quantities of water to hydrogen in a dame-sealed borosilicate glass tube at 400 degrees C for isotopic analysis. The reagent, Mg-Pt, in contrast to zinc can be prepared in every laboratory by coating a magnesium granulate with a thin layer of platinum by reaction with H2PtCl6 . 6H(2)O dissolved in acetone-ether mixture. Excellent reproducibility of the isotope ratios in hydrogen gas prepared from water samples has been obtained using 4 mu l of water and 120 mg of the reagent.

  162. Dudziak, A. Halas, S., Influence of freezing and thawing on the carbon isotope composition in soil CO2, Geoderma, 69(3-4), 1996, 209-216

    Abstract:
    The carbon isotopic composition of soil CO2 was measured during the winter of 1990/91 at two sites in the Lublin Upland (poland). In that season a period with very low air temperature occurred, during which snow covered soils were frozen. We observed variations of delta(13)C up to 3 permil. During freezing periods the variations depended on soil physical properties. In sandy soil the C-13/C-12 ratio during freezing periods increased, while in loess soil it decreased. This appears to be connected with the granulometrical composition of the soil and the size of the pores, which influence the rate of CO2 diffusion into the atmosphere. During thawing periods, when the snow was melting, the CO2 concentration increased and the C-13/C-12 ratios decreased in both types of the soil under investigation due to worse-contact of soil horizons with the atmosphere. The major winter variations in delta(13)CO(2) of soil may be useful natural markers of infiltrating waters.

  163. Trembaczowski, A., Isotopic composition of sulfates: Similarities - Differences - Misleadings, Isotopes in Environmental and Health Studies, 32(4), 1996, 405-409

    Abstract:
    In the hydrosphere sulfates of the following origin may exist: (1) evaporitic; they come from the leaching of sulfate rocks, (2) biological; formed by sulfur-oxidizing bacteria and (3) anthropogenic, which get into water with wastes, fertilizers ol acid rains. Chemical analyses map reveal sulfates in water, but their origin cannot be assessed by means of chemical analysis. The sulfates of various origin may differ in their isotopic compositions. However, sometimes we can observe the similarity of delta(34)S of sulfates whose origin was entirely different. This similarity may be so suggestive that it could be misleading. This paper presents patterns of completely different sulfates whose delta(34)S are similar, though they have nothing in common. Other tables present patterns of sulfates whose origin is similar or even the same but their delta(34)S are characterized by great variety. All of the isotopic data presented in the tables were specially chosen from some of the results of the studies of the sulfates in waters in Poland. Isotopes techniques are becoming more popular and are useful for studies in many fields. These patterns may be a warning against drawing hasty conclusions from the results of delta-measuring.


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