Observation of a change of vibrational excitation mechanism with surface temperature: HCl collisions with Au(111).
We have measured the vibrational excitation probability (Pv) of HCl incident on a Au(111) surface at kinetic energies (Ei) of 0.59 eV to 1.37 eV and surface temperatures (Ts) of 273 K to 1073 K. For all energies, the slope of the Pv as a function of Ts exhibits a sharp increase above Ts approximately 800 K. We show this change in slope and the threshold behavior of Pv to be consistent with a change in excitation mechanism from an electronically adiabatic mechanical mechanism to an electronically nonadiabatic mechanism involving excited electron-hole pairs.
Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, USA.
Q
Q
Ran
D
D
Matsiev
D J
DJ
Auerbach
A M
AM
Wodtke