Frequency shifts in inelastic electron tunnelling spectroscopy of adsorbed species

Publisher Website
Google Scholar
Abstract
The authors discuss two mechanisms which cause significant changes of mode frequencies when inelastic electron tunnelling is used to study spectra of adsorbed species. One, already well known, results from the presence of the top metal electrode in the tunnelling structure; the other results from the electric field that is applied during measurement. By analysing a simple model, they show that the applied electric field changes frequencies by the same mechanism (one depending primarily on anharmonicity of the inter-atomic potentials) as that which has previously been used to explain the top-electrode effects. The model gives a good quantitative explanation for the frequency shifts observed in the O-H stretch motion of adsorbed hydroxyl groups.