Vibrational fine structure in the Si 2pphotoelectron spectra of simple gaseous molecules

The silicon 2p photoelectron spectra of eleven molecules: SiH 4 , Si(CH 3 ) 4 , C 2 H 5 SiH 3 , (CH 3 ) 2 SiH 2 , (CH 3 ) 3 SiH, SiF 4 , SiCl 4 , (CH 3 ) 3 SiCl, (CH 3 ) 3 SiI, Cl 2 SiH 2 , and CH 3 SiF 3 , have been recorded at high experimental resolution. The spectra all exhibit broadening, and in some cases resolved fine structure resulting from the excitation of vibrations in the core-ionized molecules. Extensive use is made of the equivalent-cores approximation to aid in the interpretation of the observed vibrational structure