Infrared photodesorption: Vibrational excitation and energy transfer processes on surfaces

Abstract

Photon-stimulated desorption due to internal vibrational excitation of adsorbed molecules is a resonant phenomenon and has recently attracted considerable experimental and theoretical attention. n this paper, a brief review of prior studies is given. New results on NH 3, ND 3 and Xe in neatly adsorbed and co-adsorbed states excited by a tunable infrared laser and photodesorbed from Cu(100), NaCl and Ag films are presented to elucidate desorption mechanisms. Both single-photon and multiphoton excitation processes are examined and the velocity distributions of desorbed particles are analyzed. Various energy transfer and relaxation processes related to desorption are evaluated and a model for infrared photodesorption with particular emphasis on assessing the quantum and thermally-assisted effects is also discussed.