Desorption kinetics of alkali atoms from transition metals

Abstract

A model for the adsorption of alkali atoms on transition metals is proposed and thermal desorption spectra are analysed for the systems K/Ni(111), K/Pt(111) and K/Fe(111). The basic assumption is that the interaction energy between alkali atoms, being of dipole - dipole type, attenuates as coverage increases. The attenuation function, obtained by fitting experimental thermal desorption spectra, is used to calculate the variation with coverage of the dipole moment and the work function through the Topping model. These calculations show an excellent agreement with independent experimental measurements of the dipole moment and work function over the whole coverage range.