Electron-Hole pair creation at a Ge(100) surface by ground state neutral Xe atoms.

The energy dissipation mechanisms of a neutral gas atom or molecule interacting with a crystal surface lie at the core of adsorption/desorption dynamics. Whereas phonon excitation and thermal accommodation measurement are now common, there has been no experimental measure of the role of electronic excitations in gas-surface energy transfer. We report in this communication the first direct measurement of electronic excitation at a crystal surface by a ground state neutral gas particle. We utilize seeded molecular beam techniques to generate and scatter fast Xe atoms (1-15eV) from Ge(100) crystal and measure directly the current transient induced in the Ge crystal due to the scattering process. For several values of the Xe atom kinetic energy, 2