Penning ionization of amides by collision with He*(23S) metastable atoms

Naoki Kishimoto, Yukio Osada, Koichi Ohno

Research output: Contribution to journalConference articlepeer-review

15 Citations (Scopus)


Penning ionization of amides (formamide, acetamide, and thioacetamide) upon collision with He*(23S) metastable atoms was studied by collision-energy-resolved Penning ionization electron spectroscopy. Partial ionization cross sections were found to be larger for ionization from molecular orbitals having electron density around the C double bond O and C double bond S groups. Collision energy dependence of partial ionization cross sections indicates that interaction potentials are highly anisotropic between He*(23S) atoms and amides. The larger negative collision energy dependence of σC double bond O bands as compared to π bands shows that attractive interactions are larger around the oxygen atom for the in-plane direction rather than the out-of-plane direction. On the contrary, the larger negative collision energy dependence for ionization from non-bonding sulfur orbitals as compared to the σC double bond S band indicates that an attractive interaction around the sulfur atom was larger for in-plane or out-of-plane directions vertical to the C double bond S axis. Weak interactions around the nitrogen atoms are different from the strong attractive interaction around the `lone pair' orbital region of amines.

Original languageEnglish
Pages (from-to)183-190
Number of pages8
JournalJournal of Electron Spectroscopy and Related Phenomena
Publication statusPublished - 2001 Mar
Event8th International Conference on Electronic Spectroscopy and Structure (ICESS-8) - Berkeley, CA, USA
Duration: 2000 Aug 82000 Aug 12

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Radiation
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Spectroscopy
  • Physical and Theoretical Chemistry


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