DESORPTION-KINETICS OF ALKALI ATOMS FROM TRANSITION-METALS

A model far the adsorption of alkali atoms on transition metals is pro posed 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 inter action energy between alkali atoms, being of dipole-dipole type, atten uates as coverage increases. The attenuation function, obtained by fit ting experimental thermal desorption spectra, is used to calculate the variation with coverage of the dipole moment and the work function th rough the Topping model. These calculations show an excellent agreemen t with independent experimental measurements of the dipole moment and work function over the whole coverage range.