ABINITIO CALCULATIONS OF MOLECULAR AND ELECTRONIC-STRUCTURE OF DISILANE .2. PHOTOELECTRON AND VACUUM UV ELECTRONIC-SPECTRA

Ab initio CI calculations of the first excited singlet states of Si2H6 have been carried out. A theoretical analysis of these states in terms of Mulliken population analysis and oscillator strengths allow us to assign unambiguously the first band of the vacuum UV electronic spectrum to an A1g --> A2u Rydberg transition. A detailed analysis of the dependence of transition energies and band intensities upon intramolecular rotation has also been performed. During rotation, where A-type states appear to remain unchanged, E-type states show to suffer sensitive shifts both in energies and intensities.