Optical Radiation from Electron, Photon and Heavy Particle Bombardment of Lithium Fluoride and Lithium-Dosed Surfaces

Abstract

Comparative studies of electron, photon and ion bombardment of the same sample surface probe the various channels through which incident particle energy is dissipated, often leading to desorption. Electron or photon irradiation of alkali halides results in the swift ejection of halide atoms, leaving behind an enriched alkali metal surface from which the alkali atoms thermally desorb. Ion bombardment involves momentum transfer as well as electronic mechanisms, which results in a different surface stoichiometry at the time of desorption. This study explores how the degree of surface metallization influences the choice of the final excitation state of the desorbing particle. An important way to study the desorption products is to monitor the characteristic spectral radiation from the de-excitation of ejected species [1]. In this paper we report recent results of this type. 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.