Séminaire commun LCAR-LCPQ
Recent experimental studies of atomic (H) an molecular (NO) scattering from metal (Au) surfaces show unambiguously the important role of non-adiabatic effects in energy exchange between projectile and surface degrees of freedom. I discuss two approaches endeavored to quantitatively describe and understand those effects in microscopic detail : a Local Density Friction Approximation (LDFA) and an Independent-Electron Surface Hopping (IESH) method. The former considers the interaction between projectile translational degrees of freedom and electron-hole pairs of a metal in framework of friction theory with electron density dependent friction coefficient. The latter approach describes the non-adiabatic dynamics of electrons of the metal conduction band explicitly, thus, going beyond perturbative frictional approach in studying vibrational excitation and de-excitation at the metal surface.