Determination of the molecular symmetry of acetylene on Ni(001) by electron-impact scattering

Angle-dependent electron-energy-loss measurements of acetylene on Ni(001) are used to deduce molecular symmetry on the surface by consideration of selection rules for vibrational excitation by impact scattering. Chemisorbed acetylene has Cs symmetry with a mirror plane along 110 and a molecular plane tilted relative to the surface. © 1983 The American Physical Society.