title: Ammonia adsorption on and diffusion into thin ice films grown on Pt(111).
abstract: Ammonia adsorption on and diffusion into thin ice films grown on a Pt(111) surface were studied using Fourier transform infrared spectroscopy (FTIR) and thermal desorption spectroscopy. After exposing the crystalline ice film to ammonia molecules at 45 K (ammonia/ice film), we have detected an intriguing feature at 1470 cm(-1) in the FTIR spectra, which is derived from the adsorption of ammonia on the ice with a characteristic structure which appears in thin film range. The peak intensity of this feature decreases gradually as the thickness of the substrate ice increases. In addition, we have detected a feature at 1260 cm(-1) which appears after annealing the ammonia/ice film. The feature corresponds to the ammonia molecules which reach the ice/Pt(111) interface through the ice film. Intriguingly, the intensity of this feature decreases with the ice thickness and there is a linear relation of the peak intensity of the features at 1470 and 1260 cm(-1). We propose a model in which the solubility of the ammonia molecules is much higher for the thin ice film than that for the ideal ice.
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Takaoka
authors.forename: M
authors.initials: M
authors.lastname: Inamura
authors.forename: S
authors.initials: S
authors.lastname: Yanagimachi
authors.forename: I
authors.initials: I
authors.lastname: Kusunoki
authors.forename: T
authors.initials: T
authors.lastname: Komeda