Si core-level excitation of hexamethyldisilane studied by synchrotron radiation and multiple-scattering X α calculation

The Si 1s, Si 2s and Si 2p core-level photoabsorption spectra of hexamethyldisilane have been recorded by synchrotron radiation and calculated by the multiple-scattering (MS) X α method. The results of the calculation are in semiquantitative agreement with the experimental spectra. The relative intensity of corresponding transitions at the (1s, 2s) or (2p) edges differs greatly on account of atomic-like propensity rules (s → p, p → s, d). Comparison of the gas phase and solid state Si 2p spectra with the MS-X α results indicates that many of the features in the Si 2p spectrum of hexamethyldisilane correspond to transitions to states of mixed valence and Rydberg character.