Theory of photodesorption

Abstract

A theory for photodesorption of chemisorbed species is developed. Two cross sections are computed—one for photodesorption in the excited state with subsequent free atomic fluorescence and the other, the total desorption cross section in any state. A decay mechanism involving surface plasmon and particle-hole pair excitations is introduced to account for nonradiative deexcitation processes. A comparison is made to other mechanisms such as photoelectron-stimulated desorption. Estimates show that the cross section is of sufficient magnitude to be readily detected in the laboratory.