Rydberg—valence mixing in the C 1s excited states of CH 4 probed by electron spectroscopy

Abstract

The C1s → ndt 2 Rydberg series and the ν = 1 vibrational levels of the symmetric mode ( ν 1) in the dominant C1s → npt 2 series are clearly identified in the C 1s high-resolution electron-yield spectrum of CH 4. In the resonance Auger electron spectra the participant Auger decay rate following the C1s → 3sa 1, 3pt 2 and 3dt 2 excitations are 5.5%, 2.5%, and 3.7% of the total Auger decays, respectively, indicating that these Rydberg states do not have so strongly mixed valence character. The ordering of the valence contribution as 3sa 1 > 3dt 2 > 3pt 2 is consistent with the theoretical prediction.