We present ab initio multireference configuration interaction (MRCI) calculations for the potential energy surfaces of HCCl in its three low-lying electronic states (X̃1 A′, ã3A″ and Ã1 A″), and for the spin-orbit coupling between the X̃ and ã states. The two singlet states become a degenerate 1Δ state in collinear geometries. The potential energy surfaces are interpolated from 6075 MRCI energy points. The final surfaces are slightly adjusted using a coordinate and energy scaling approach. The resulting T e value is 2122.0 cm-1 for ã3 A″ and 12209.8 cm-1 for Ã1 A″. Vibrational energy levels of DCCl and HCCl are computed for the three states taking into account the Renner-Teller effect and the spin-orbit coupling. The calculated vibronic energy levels are in good agreement with the available experimental values. It is found that the spin-orbit effect is pronounced in the X̃ and ã states.
ASJC Scopus subject areas
- Molecular Biology
- Condensed Matter Physics
- Physical and Theoretical Chemistry