Calculation of X-ray and photoelectron emission of solids with a semi-empirical LCAO method: graphite

The extended Huckel LCAO method is used in a calculation of one- electron energy bands and wavefunctions of a two-dimensional layer of graphite. After adjustment of the calculated sigma - pi overlap to that obtained by Painter and Ellis (1970) in an ab initio calculation good agreement is obtained with experiment for the polarized carbon X-ray emission of graphite. It is shown that, in the experiments performed so far, complete polarization was not achieved. An estimate of the valence band as observed in X-ray photoelectron spectroscopy is also presented.