Ran Q, Matsiev D, Auerbach D J, Wodtke A M
Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, USA.
Phys Rev Lett. 2007 Jun 8;98(23):237601. doi: 10.1103/PhysRevLett.98.237601.
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.
