Selectivity of bond-breaking in electron-induced dissociation of hydrocarbon films on Au surfaces

Electron-induced dissociation (EID) processes in organic and polymer films are important in a variety of applications. One scientific issue concerns the selectivity of low-energy electron bombardment to cleave a single C-H bond in hydrocarbon condensed films or adsorbed layers. We have undertaken combined TPD and FT-IRAS studies to identify and determine the purity of the surface species produced by EID of cyclohexane and benzene films on Au(1 1 1). Experimental evidence strongly supports a conclusion that EID of cyclohexane and benzene monolayer and multilayer films using incident electrons with an energy of 30 eV can be used to cleave a single C-H bond and produce a single chemisorbed product with high selectivity. An important consequence of these observations is that a variety of adsorbed hydrocarbon intermediates on Au(1 1 1) and other metal surfaces can be prepared in this manner, spectroscopically characterized, and used in studies to advance the understanding of chemical bonding, reactions and catalysis at surfaces. (C) 2001 Elsevier Science B.V. All rights reserved.