Vacuum UV Photoabsorption Spectra of Silane and Disilane: Molecular Orbital Calculation of Electronic States

Ab initio molecular orbital calculations have been performed for the assignment of vacuum ultraviolet photoabsorption spectra of SiH 4 and Si 2 H 6 . Strong peaks in the absorption spectra are primarily due to Rydberg transitions of the Si–H and Si–Si bonding electrons to the 4 s , 4 p , and 4 d orbitals. Substantial contributions of the valence excitations are revealed.