Davydov splitting of vibrational spectra of adsorbates

Abstract

A monolayer of adsorbed molecules that form a two-dimensional lattice whose unit cell contains several orientationally nonequivalent molecules is considered. General expressions for the polarizability tensor of this system and the frequencies and integral intensities of s-and p-polarized spectral lines with regard for the electronic polarizability components of the molecules are found. As a result, the discrepancy between the calculated and experimentally observed values of the Davydov splitting for the system CO/NaCl(100) is reduced from 25 to 5%.