Photoelectron spectroscopy studies and calculation of the energy bands of CsAu and RbAu

Abstract

Presents XPS and UPS photoemission data for polycrystalline RbAu and CsAu. The spin-orbit splittings of the valence bands is employed to interpret the spectra in terms of flat bands. The experimental density of states distribution is compared with new relativistic KKR band calculations. In these calculations a significant charge transfer from the alkali metal to the gold site has been found and, consequently, a calculation starting from an ionic crystal potential has been employed. The resulting bands compare well with the photoemission spectra. The unexpected small photoionisation cross section from the Au d bands and a significant deviation of the surface composition from the stoichiometric bulk composition are discussed.