Chemical shift of Si 2p core level in SiOx calculation of relaxation contribution

Starting from the treatment of the electron self‐energy in the linear shielded potential approximation relaxation energies for the excitation of Si 2p‐electrons in SiOx compounds are calculated. It is shown that the differences ≈ 5 eV between one‐electron Hartree‐Fock values and binding energies found by means of XPS are caused by dynamical relaxation in the electronic system. The contribution of relaxation to the oxygen‐induced shift of the Si 2p core level is estimated. The total chemical shift with x can be explained in terms of variation of core‐level shift due to solid‐state effects and relaxation energy. The contribution of the Fermi level shift seems to be negligible.