Advertisement

Photo- and Penning Ionization of Molecules in the Gas Phase and in the Liquid Phase

  • Harald Morgner
Part of the NATO ASI Series book series (NSSB, volume 326)

Abstract

Electron spectroscopy has contributed a great deal to the understanding of the properties of matter, let it be atoms, molecules or matter in the condensed phase. The common feature of these spectroscopies consists in analysing the kinetic energy of electrons that have experienced an interaction with the probe to be investigated. One way of performing the experiment is to start with a beam of electrons of known kinetic energy. If the loss of kinetic energy due to interaction with the probe is recorded one talks about electron energy loss spectroscopy (EELS). The energy loss spectrum is characteristic of the target atoms or molecules, but the detailed interpretation of such spectra is not always straightforward since the theoretical description of the electron molecule interaction is not simple. Still, many studies of this kind have been performed on gas phase molecules 1,2 and first attempts to use this experimental tool for the investigation of molecules in the liquid phase have been reported 3,4. Another widely used technique, applicable for primary electron beams of several keV energy, is to observe electrons which originate from ions produced by the impact of the primary beam. If the ion is created by removal of an electron out of a core hole then the ion is in a highly excited state and will decay via an Auger process by emission of a second electron into a doubly charged ion. The spectroscopy of these electrons (Auger electron spectroscopy=AES) has developed into a broad field in atomic and molecular physics 5 and has become a routine tool in the analysis of solid surfaces 6. Liquid surfaces have been investigated by this technique as well 2, but its specific contribution to the understanding of liquid surfaces is yet to be understood.

Keywords

Electron Spectroscopy Electron Energy Loss Spectroscopy Electron Energy Spectrum Metastable Atom Metastable Helium Atom 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    J. N. H. Brunt, G. C. King and F.H. Read, A study of resonance structure in helium using metastable excitation by electron impact with high energy resolution, J. Phys. B 10: 433–48 (1977).ADSCrossRefGoogle Scholar
  2. 2.
    H. Kuppermann, W. M. Flicker and D. A. Mosher, Electronic spectroscopy of polyatomic molecules by low-energy, variable-angle electron impact, Chem. Reviews 79: 77–90 (1979).CrossRefGoogle Scholar
  3. 3.
    R. E. Ballard, J. Jones, D. Read, A. Inshley and M. Cranmer, Auger and electron energy loss studies on liquid surfaces, Chem. Phys. Lett, 147: 629–31 (1988).ADSCrossRefGoogle Scholar
  4. 4.
    F. Eschen, M. Heyerhoff, H. Morgner and M. Wulf, unpublished results (1993) M. Heyerhoff, Diplom Thesis, University Bochum, (1993).Google Scholar
  5. 5.
    W. Mehlhorn in Atomic Inner-Shell Physics, ed. B. Craseman, Plenum, New York (1985).Google Scholar
  6. 6.
    G. Ertl and J. Küppers, “Low Energy Electrons and Surface Chemistry”, VCH Verlagsgesellschaft, Weinheim (1985).Google Scholar
  7. 7.
    K. Siegbahn, C. Nordling, G. Johansson, J. Hedman, P. F. Hedin, K. Hamrin, U. Gelius, T. Bergmark, L. O. Werme, R. Manne, Y. Baer, “ESCA Applied to Free Molecules”, North Holland, Amsterdam (1969).Google Scholar
  8. 8.
    D. Wagner, W. M. Riggs, L. E. Davis, “Handbook of X-ray photoelectron spectroscopy” ed. by G. E. Muilenberg, Perkin-Elmer Corp., Physical - Electronics Division, Eden Prairie (1978).Google Scholar
  9. 9.
    H. Siegbahn and K. Siegbahn, ESCA applied to liquids, J. Electr. Spectr. Rel. Phen. 2: 319–25 (1973).CrossRefGoogle Scholar
  10. 10.
    D. W. Turner, A. D. Baker, C. Baker and C. R. Brundle. “Molecular Photoelectron Spectroscopy, A Handbook of 584 Å Spectra”, Interscience, London - New York (1970).Google Scholar
  11. 11.
    K. Kimura, S. Katsumata, Y. Achiba, T. Yamaski and S. Iwata, “Handbook of HeI Photoelectron Spectra of Fundamental Organic Molecules”, Japan Scientific Societies Press, Tokyo (1981).Google Scholar
  12. 12.
    H. J. Freund and M. Neumann, Photoemission of molecular adsorbates, Appl. Phys. A 47:3–23 (1988).ADSCrossRefGoogle Scholar
  13. 13.
    R. Morgenstern, A. Niehaus and M. W. Ruf, Angular distribution of photo- electrons, Chem. Phys. Lett. 4: 635–8 (1970). E. S. Chang, Angular distributions of photoelectrons with analysis on the rotational states of H2, J. Phys. B 11:L69–74 (1978).ADSCrossRefGoogle Scholar
  14. 14.
    L. Nemec, J. M. Gaehrs, L. Chia and P. Delahay, J. Chem. Phys. 66: 4450 (1977).ADSCrossRefGoogle Scholar
  15. 15.
    R. R. Ballard, J. Jones and E. Sutherland, Measuremant and calibration of the He(I) photoelectron spectra of gaseous and liquid ethanediol, propanediol and formamide, Chem. Phys. Lett, 112: 306 (1984).ADSCrossRefGoogle Scholar
  16. 16.
    F. M. Penning, Über Ionisation durch metastabile Atome, Die Naturwissenschaften 15: 818 (1927).ADSCrossRefGoogle Scholar
  17. 17.
    V. Cermảk, Retarding-potential measurements of the kinetic energy of electrons released in Penning ionization, J. Phys. 44: 3781–6 (1966).Google Scholar
  18. 18.
    H. Hotop and A. Niehaus, Reactions of excited atoms and molecules with atoms and molecules, Zeitschrift für Physik 215: 395–407 (1968).ADSCrossRefGoogle Scholar
  19. 19.
    W. Keller, H. Morgner and W. A. Müller, Probing the outermost layer of a free liquid surface. Electron spectroscopy of formamide under He(23S) impact, Mol. Phys. 57: 623–36 (1986).ADSCrossRefGoogle Scholar
  20. 20.
    H. Hotop and G. Hübler, Photoelectron and Penning ionization electron spectrometry with differential retarding field analyzer, J. Electr. Spectr. Rel. Phen. 11: 101–21 (1977).CrossRefGoogle Scholar
  21. 21.
    T. Koopmans, Physica 1: 104 (1933).ADSCrossRefMATHGoogle Scholar
  22. 22.
    K. Beckmann, O. Leisin and H. Morgner, Excitation transfer into bound and continuum states investigated by optical and electron spectroscopy, Mol. Phys. 59: 829–43 (1986).ADSCrossRefGoogle Scholar
  23. 23.
    H. Morgner and H. Seiberle, Transition state spectroscopy with electrons as studied by 3D-trajectory calculations of the reaction He++ Br2 ----> He+Br- +Br, submitted to Can. J. Physics, (Polanyi-Special Issue), to appear in 1994.Google Scholar
  24. 24.
    W. Keller, H. Morgner and W. A. Müller, He(23S) and hydrogen bonding molecules. A comparative study of He(23S) Penning ionization versus Hel photoionization for formamide and N-methylformamide, Mol. Phys. 57: 637–44 (1986).ADSCrossRefGoogle Scholar
  25. 25.
    A. Dalgarno and A. E. Kingston, Properties of the metastable helium atoms, Proc. Phys. Soc. 72: 1053–60 (1958).ADSCrossRefGoogle Scholar
  26. 26.
    B. Haug, H. Morgner and V. Staemmler, Experimental and theoretical study of Penning ionisation of H2O by metastable helium He(23S), J. Phys. B 18: 259–74 (1985).ADSCrossRefGoogle Scholar
  27. 27.
    A. W. Hertzner, M. Schoen and Morgner, The influence of long range electrostatic forces on static properties of a quasi-Stockmayer fluid, Mol. Phys. 73: 1011–29 (1991).Google Scholar
  28. 28.
    A. W. Hertzner and H. Morgner, 1991, unpublished results.Google Scholar
  29. 29.
    M. Matsumoto and K. E. Gubbins, Hydrogen bonding in liquid methanol, J. Chem. Phys. 93: 1981–94 (1990).ADSCrossRefGoogle Scholar
  30. 30.
    H. Siegbahn, L. Asplund, P. Kelfve, K. Hamrin, L. Karlsson and K. Siegbahn, ESCA applied to liquids. II. valence and core electron spectra of formamide, J. Electr. Spectr. Rel. Phen. 5: 1059–79 (1974).CrossRefGoogle Scholar
  31. 31.
    J. Ladell and B. Post, The crystal structure of formamide, Acta Crystallographica 7: 559–64 (1954).CrossRefGoogle Scholar
  32. 32.
    H. Morgner, The investigation of liquid surfaces by electron spectroscopy, 5th Int. Conf. Electr. Spectr., Kiev (1993) and J. Electr. Spectr. Rel. Phen. submitted (1993).Google Scholar
  33. 33.
    H. Siegbahn, L. Asplund, P. Kelfve and K. Siegbahn, ESCA applied to liquids. III*. ESCA phase shifts in pure and mixed organic solvents. J. Electr. Spectr. Rel. Phen. 7: 411–9 (1975).CrossRefGoogle Scholar
  34. 34.
    H. Siegbahn, Electron spectroscopy for chemical analysis of liquids and solutions, J. Phys. Chem. 89: 897–909 (1985).CrossRefGoogle Scholar
  35. 35.
    H. Morgner, J. Oberbrodhage, K. Richter and K. Roth, The gas-liquid phase transition shift at surfaces: experimental method and interpretation, J. Electr. Spectr. Rel. Phen. 57: 61–77 (1991).CrossRefGoogle Scholar
  36. 36.
    H. Morgner, J. Oberbrodhage, K. Richter and K. Roth, Surface segregation of a binary liquid mixture as studied by metastable impact electron spectroscopy, Mol. Phys. 73: 1295–1306 (1991).ADSCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1994

Authors and Affiliations

  • Harald Morgner
    • 1
  1. 1.Institut für ExperimentalphysikUniversität Witten/HerdeckeWittenGermany

Personalised recommendations