Acetone, (CH3)2CO and (CD3)2CO, adsorbed on Ag(111) at 95 K was studied using using thermal, photon, and electron activation. Adsorption and desorption involve no dissociation. The temperature-programmed desorption (TPD) spectra exhibit three resolvable peaks, two of which (146 and 134 K) are assigned to the first layer and the third (127−134 K) to multilayers. TPD, after sequentially dosing 1 ML of (CD3)2CO followed by 1 ML of (CH3)2CO, shows extensive mixing of the two adsorbates throughout the full width of the desorption peaks. This suggests rapid motion, on the TPD time scale, below the onset of desorption (120 K). RAIRS analysis at 95 K indicates that the orientation of adsorbed acetone is coverage-dependent, but the CO bond remains nearly parallel to the Ag(111) surface at all coverages. At the lowest coverages the average C−C−C plane position is 50° from the surface normal; at higher coverages (up to monolayer) this plane tilts toward the surface normal (22°). Dissociation and desorption of adsorbed (CH3)2CO are initiated by 100 eV electrons; TPD products include ketene, methane, and high-temperature (CH3)2CO derived from acetone enolate. RAIRS after electron irradiation provides evidence for electron-induced reorientation in which the CO bond moves away from the surface plane. The cross section for loss of parent was of order 10-16 cm2. Photon irradiation at 248 and 193 nm produced no effects with cross sections higher than 10-21 cm2.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.