Benzene chemisorption on palladium surfaces. II. Resonance electron scattering and overtone vibrations

Abstract
Inelastic electron scattering from the vibrational modes of benzene chemisorbed on Pd(100) and Pd(111) at room temperature show energy-dependent structure and mode selectivity. The results are characteristic of resonance scattering via temporary negative-ion states. We observe resonance behavior in the totally symmetric C-H stretching mode and its overtones, ν1(n) (n=1,2,3), near 2.5 eV impact energy, and associate it with a gas-phase benzene resonance at higher energy.