Vibrational fine structure on the core level photoelectron lines of small polyatomic molecules

Abstract

The C 1s and O 1s photoelectron spectra of CH 4, CD 4, CF 4, C 2H 6 and CO 2 have been measured with high photon energy resolution. Vibrational fine structure on the main line (single hole state) could be resolved for all molecules except CF 4. Even in the case of C 2H 6 where several modes are expected to couple, two prominent progressions are visible. The fine structure on the C 1s line of CO 2 results, as expected, from the totally symmetric stretching mode, whereas the O 1s main line is dominated by the antisymmetric stretching mode ofσ u symmetry due to vibronic coupling.