A theoretical investigation of vibrational fine structure accompanying core ionization in hydrogen cyanide and acetylene

Non-empirical calculations at the STO-4.31G level are reported on the ground-state and core-ionized states of HCN and H ₂C ₂. An analysis of the changes in bond lengths and force constants for the normal modes involving stretching vibrations allows direct computation of the overall band profiles for the core-ionized levels. The distinct asymmetries arising from the vibrational excitations accompanying core ionizations suggest that the experimental investigations of these systems would be eminently worthwhile.