KINETICS OF THE INTERACTION OF AZOMETHANE WITH LOW-ENERGY ELECTRONS ON AG(111)

The thermal and electron-induced chemistry of CH3N2CH3 on Ag(111) has been studied using temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). CH3N2CH3 adsorption on Ag(111) is completely reversible, with desorption peaks at 180 and 130 K for monolayer and multilayer, respectively. Electron irradiation on 1 ML of CH3NCH3 results in almost quantitative electron stimulated desorption (ESD) of N2. ESD of CH3 and CH4, as well as traces of C2H6 and C2H2, is also observed. The retained fragments desorb in TPD mainly as H-2 and CH4. At 54.7 +/- 0.3 eV, the electron-induced decomposition (EID) cross section is about 7 X 10(-17) cm2. The EID cross section increases with electron energy and has a threshold of about 10 eV. The EID is attributed to ionization of chemisorbed azomethane.