Anab initiostudy of the chlorine x-ray emission spectra of the CH3Cl molecule

The x-ray emission processes associated with K, L1, and L2,3 chlorine core shell ionization in the CH3Cl molecule have been studied using ab initio molecular orbital methods. The energy and absolute transition rates of XES processes have been calculated. Comparison with atomic calculations is used to identify weak molecular effects. For the Kβ spectrum relaxation terms must be included to obtain good agreement between the calculated and experimental spectra. It is concluded that three transitions are major contributors to the Kβ spectrum. However, a one-center model is adequate to account for the Kα spectrum. Uncertainty regarding the extent of satellite contribution to the experimental L2,3 spectrum and the breakdown of the single particle model has made direct comparison between theory and experiment difficult. New measurements and a more refined theoretical approach beyond the relaxed Hartree–Fock model are desirable. The L2,3 and L1 or Kβ emission spectra provide complementary information for probing the valence electronic structure of the CH3Cl molecule.