Accession Number:

ADA199626

Title:

Electronic Interactions of Electrons, Photons, and Atoms with Material Surfaces

Descriptive Note:

Final rept. Apr 1986-Apr 1988

Corporate Author:

VANDERBILT UNIV NASHVILLE TN

Report Date:

1988-08-31

Pagination or Media Count:

16.0

Abstract:

The intent of this research program was to elucidate the microscopic mechanisms by which the energy of incoming beams of atoms, ions, electrons and photons is absorbed, localized and redirected to produce neutral-particle desorption from surfaces and subsequent surface modification of restructuring. The model system LiF was used, and the results compared with measurements of electronically desorbed Li-atoms adsorbed on other substrates. This study explored how the degree of surface metallization influences the choice of the final excitation state of the desorbing particle. Measurements were made to compare the desorption of excited state neutral lithium from lithium fluoride by electron, photon and ion bombardment and from lithium-dosed tungsten and lithium-dosed glass by electron and photon bombardment. In the electron and photon desorption experiments, only the first lithium resonance line is observed. These results contrast with the ion sputtering results, where emissions from higher excited states were observed. This suggests that the presence of a metal rich surface provides a channel for de-excitation of excited lithium states which are above the lithium metal Fermi energy.

Subject Categories:

  • Physical Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE