IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Tuesday Sessions
       Session SS3-TuP

Paper SS3-TuP13
Collision Induced Process of Adsorbates on Ni(100)

Tuesday, October 30, 2001, 5:30 pm, Room 134/135

Session: Adsorption/Desorption Poster Session
Presenter: I. Kusunoki, IMRAM, Tohoku University, Japan
Authors: T. Takaoka, IMRAM, Tohoku University, Japan
M. Inamura, IMRAM, Tohoku University, Japan
S. Yanagimachi, IMRAM, Tohoku University, Japan
I. Kusunoki, IMRAM, Tohoku University, Japan
Correspondent: Click to Email
Surface reactions are usually described as reactions between adsorbates on surfaces. However, effect of collision of molecules in gas phase to surfaces is drawing attention at present. In this work, the collision effect on a N@sub 2@ monolayer, a benzene multilayer, and CO and H coadsorbates on Ni(100) surfaces were investigated. The experiment was carried out in the homemade molecular beam apparatus, which was equipped with a FTIR spectrometer. A supersonic molecular beam technique was used for the control of translational energy of Xe atoms. (1) N@sub 2@ on the Ni(100) surface In FTIR spectra of a Ni(100) c(2x2)-N2 surface, a peak was observed at 2205 cm@super -1@. From the analysis of FTIR spectra recorded after the surface began to be irradiated with Xe beam, it was found that the desorption of N2 molecules is induced by collision with the Xe atoms. The desorption is induced when Xe energy is above threshold energy of 0.8 eV. The threshold energy can be explained with a classical collisional model. (2) benzene multulayer on the Ni(100) surface The effect of the collision onto a multilayer of molecules has been studied. No desorption was observed when a benzene multilayer on the Ni(100) surface was irradiated with Xe atoms with energy of 1.2 eV. The energy transferred from the Xe atom was probably dissipated in condensed molecules and no desorption was observed. (3) CO and H coadsorbates on the Ni(100) surface After the Ni(100) surface was pre-exposed to H@sub 2@ and subsequently exposed to CO, a peak at 2100 cm@super -1@ was observed. In FTIR spectra recorded after the surface began to be irradiated with the Xe beam, decrease of the intensity of the 2100 cm@super -1@ peak and increase of the intensity of a 1950 cm@super -1@ peak with increasing Xe irradiation were observed. It was found that the adsorption site of CO is changed owing to the collision of Xe atoms and a cross section for the change is dependent on the Xe energy.