Vibrations of Neutrally Adsorbed Atoms on Transition Metal Surfaces

Abstract

An electron band model is used to calculate the vibration frequency of a neutrally adsorbed atom such as hydrogen on a transition metal surface. The bond length increases with increasing adatom co-ordination number, and in the atop position is greater than in the corresponding metal-adatom dimer. For strong bonding there is little difference between the vibration frequency in the atop position and of the dimer, but for weak binding large shifts occur. A simple relation between the adsorption energy and vibration frequency is derived. Bond relaxation is found to be of great importance in determining vibration frequencies.