SI CORE-LEVEL EXCITATION OF HEXAMETHYLDISILANE STUDIED BY SYNCHROTRON-RADIATION AND MULTIPLE-SCATTERING X-ALPHA CALCULATION

The Si1s, Si2s and Si2p core-level photoabsorption spectra of hexameth yldisilane have been recorded by synchrotron radiation and calculated by the multiple-scattering (MS) X alpha method. The results of the cal culation are in semiquantitative agreement with the experimental spect ra. The relative intensity of corresponding transitions at the (Is, 2s ) or (2p) edges differs greatly on account of atomic-like propensity r ules (s --> p, p --> s, d). Comparison of the gas phase and solid stat e Si2p spectra with the MS-X alpha results indicates that many of the features in the Si2p spectrum of hexamethyldisilane correspond to tran sitions to states of mixed valence and Rydberg character.