VIBRATIONALLY RESOLVED SI 2P PHOTOABSORPTION SPECTRUM OF SICL4

We report on a high-resolution study of the Si 2p photoabsorption spectrum of SiCl4 in the gas phase. Characteristic differences in the intrinsic widths of the resonance lines allow a distinction of excitations to valence and Rydberg orbitals, respectively. The Rydberg resonances are found to be narrow and split into vibrational substrates from symmetric-stretching vibrations, providing information-on the basis of a Franck-Condon analysis-on vibrational energies and equilibrium internuclear distances of the core-excited molecule. Thermal population of excited vibrational levels in the molecular ground state has to be taken into account for a proper description of the spectrum.