Abstract

The possibility of desorption of atomic or molecular species from surfaces occurring by non-thermal means has recently attracted considerable interest.¹ One of the most intriguing cases is that of desorption from the surface of a metal substrate, for which the lifetimes of excited, non-equilibrium states in both the bulk and surface region are expected to be extremely short. In this paper, we report results on the desorption of NO from chemisorbed states on a Pd (111) surface induced by exposing the surface to laser radiation of 2-eV photons in a 200 fsec pulse. Analysis of these results in conjunction with our earlier study of NO desorption from Pd (111) by nanosecond laser pulses² indicates that by depositing energy into the surface on a sub-picosecond timescale we are able to observe a non-thermal desorption mechanism. Here we outline the nature of our experiment and present data concerning the yield and vibrational energy distribution for the desorbed NO molecules.

© 1989 Optical Society of America