Low-Energy Electron Induced Decomposition of Fe(CO)5 Adsorbed on Ag(111)

摘要

The low-energy electron induced decomposition of monolayer and multilayer Fe(CO)son a Ag(111) surface was examined with temperature programmed desorption (TPD), Auger elect Ton spectroscopy (AES), and low-energy electron diffraction (LEED). In the absence of electron bombardment, Fe(CO)s thermally desorbs from Ag(III) in monolayer (181 K) and multilayer (170 K) desorption states with minimal decomposition. Low-energy (3-132 eV) electron bombardment converts adsorbed Fe(CO)5 into Fcx(CO)y clusters. These new species are much less susceptible to electron induced decomposition than adsorbed molecular Fe(CO)5. Fex(CO)y clusters thermally decompose near 330 K, liberating gas phase CO and depositing Fe. particles on the Ag(l 1 1) surface. Little C or 0 is present on these Fe, clusters. The Fex species do not exhibit metallic character, based on their inability to subsequently adsorb CO. The total cross section for the electron induced decomposition of Fe(CO), adsorbed on Ag(1 1 1) is (1-14) x 10-16 cm2 for electrons in the energy range 3-132 eV, comparable to the gas phase Fe(CO)5 cross section for electron-induced processes. Iron Carbonyl, Electron Stimulated, Iron Films, Desorption.