AVS 49th International Symposium
    Surface Science Wednesday Sessions
       Session SS1-WeA

Paper SS1-WeA1
Interaction of Gas-phase H Atom with Metal Surfaces : Cu(111) vs Pt(111)

Wednesday, November 6, 2002, 2:00 pm, Room C-108

Session: Gas-Surface Dynamics
Presenter: S.J. Lee, Seoul National University, Korea
Authors: S.J. Lee, Seoul National University, Korea
J. Kim, Seoul National University, Korea
J. Lee, Seoul National University, Korea
Correspondent: Click to Email
The gas-phase H atoms of thermal energy impinging upon metal surface undergo reflection, adsorption, or abstraction of a surface H atom. The probability of each process strongly depends on the inelastic nature of the H-metal surface collision. Inelastic energy loss via phonon excitation is expected to be quite inefficient because of the light mass of H atom. Recently, Nienhaus et al. (1) have experimentally shown that H atom collision with metal surfaces induces e-h pair excitation. Then, one can raise the following interesting questions; 1) Is e-h pair excitation a dominant inelastic loss mechanism in H-metal surface collision? 2) If it were the case, what would be the effect of electronic band structure of metal in its interaction with H atom? In order to gain further insight into these questions, we have measured and compared the initial sticking probability(S@sub 0@), saturation coverage(@theta@@sub s@), and abstraction cross section(s@sub abs@) for hydrogen atom at Cu(111) and Pt(111) at 90K. We measure S@sub 0@=0.72, @theta@@sub s@=0.95ML, and s@sub abs@=1.30Å for Pt(111) and S@sub 0@=0.45, @theta@@sub s@=0.32ML, and s@sub abs@=5.5Å for Cu(111). We interpret the results in terms of e-h pair excitation whose efficiency is determined by the electron density of state at the Fermi level.