PHOTOELECTRON SPECTRA AND QUANTUMCHEMICAL CALCULATIONS OF PERCHLOROCYCLOPOLYSILANES

He(I)-PE-spectra of perchlorocyclopolysilanes (SiCl 2 ) 4 , (SiCl 2 ) 5 and (SiCl 2 ) 6 are recorded and interpreted by semiempirical PM3 calculations. HOMOs may be described by antibonding π* interactions of σ{SiSi)3p and (Cl)3p lone pair orbitals. First ionization potentials appear near 9 eV and increase in the order Si 4 < Si 6 < Si 5 . HOMO-LUMO studies suggest, that intramolecular charge transfer might be responsible for the unusual low energy of UV absorption bands.