Adsorption and photoexcitation of NO on Ag/Pt(111)

The adsorption and photoreaction of NO on Ag films deposited on Pt(111) wer e investigated at 90 K by reflection-absorption infrared spectroscopy (RAIR S). Similar to Ag(111), NO molecules were found to be converted into (NO)(2 ) and N2O on the Ag films. At an Ag thickness of 1 ML, however, a new adsor ption state that reveals a RAIRS band at 1848 cm(-1) is present on the surf ace. The (NO)(2) dimer species was found to react into N2O, while the react ion of the new species was substantially suppressed. Upon photon irradiatio n with a wavelength of 193 nm. the three adsorption species on Ag(1 ML)/Pt( 111) were depleted from the surface. The origin of the newly found species and the photoreaction mechanism are discussed. (C) 2001 Elsevier Science B. V. All rights reserved.