Comparative study of vibrations in submonolayer structures of potassium on Pt(111)

Abstract

We present results of a comparative study of the vibrational spectrum and local density of phonon states in ordered p(2 x 2) and (√3 x √3)R30° structures formed by potassium atoms on the Pt(111) surface. The calculations were performed with tight-binding interatomic interaction potentials. It was found that the mode associated with vertical displacements of K adatoms has an energy of about 20 meV in both K structures. The strength and energy of this mode slightly decreases with increasing coverage. This result is in good agreement with available experimental data. As in time-resolved second harmonic generation measurements, we observed low frequency modes for both structures considered, which are caused by the interaction of potassium with the second layer of the substrate.

Joule Heating in Single-Molecule Point Contacts Studied by Tip-Enhanced Raman Spectroscopy

“…The dissipation into surface phonons is associated with the Debye cutoff. While this value depends on the surface (Ag, 22 meV; Au, 16 meV; Cu, 30 meV; Pt, 24 meV), 54,55 it lies below the C 60 vibrations (30−200 meV). The phonon−phonon interaction is inefficient for higher energy modes because they require multiple phonon−phonon scattering.…”