Spectroscopic studies of ethylene adsorption on oxygen-modified Ag(111) athigh pressures

2-Iodoethanol adsorbs on Ag(1 1 1) to form 2-hydroxyethyl species which rea ct at similar to 230 K to eliminate water and ethylene and to deposit speci es of stoichiometry C2H4O. At high coverages, this forms predominantly oxam etallacyclic species which exhibit vibrational modes at 759, 972 and 1069 c m(-1). The oxametallacycle thermally decomposes forming acetaldehyde. The r eflection-absorption infrared spectra of both ethylene and ethylene oxide a dsorbed on oxygen-activated Ag(1 1 1) at 300 K under a pressure of 1 Torr s how that they react to form both acetaldehyde and ethylene oxide species. E thylene oxide adsorbs at high pressures via the oxygen atom with the molecu lar plane tilted with respect to the (1 1 1) surface. All of the adsorbed e thylene oxide and the majority of the acetaldehyde desorb on heating to 390 K, with the remainder of the acetaldehyde being removed by heating to 450 K. These results are in accord with previous temperature-programmed desorpt ion data which showed the formation of acetaldehyde, ethylene oxide and CO2 in this temperature range. (C) 2001 Elsevier Science B.V. All rights reser ved.