Electronic structure and optical properties of thallium

Abstract
A relativistic APW calculation of the bandstructure of thallium is presented. Exchange has been evaluated according to the Slater free-electron expression with parameter 1 or 2/3. In using the Kohn-Sham value the calculated Fermi surface is in very good agreement with dHvA experiments, the position of the 5d doublet near the bottom of the valence band is found 2.6 eV above the experimental XPS value. With full Slater exchange the 5d doublet falls, relative to EF, at a position near the XPS value, while the agreement with Fermi surface data becomes worse in comparison to that of Kohn-Sham exchange. The omega 2 epsilon 2 spectra calculated with alpha =2/3 exchange are in good accordance with experiment, especially for photon energies h(cross) omega <3 eV.