Ab initio calculation of the potential energy curves and spectroscopic properties of low-lying electronic states of CH+ molecular cation

Abstract

The combined use of the MRCI-SD(T) method with the cc-pV6Z basis set has enabled us to determine the potential energy curves of the molecular cation whose fundamental state lies above the corresponding state of its neutral parent at the dissociation limit. With the accurate potential energy curves thus obtained, we have calculated spectroscopic constants which show good agreement with the experimental and other theoretical values available in the literature. To account for perturbations where necessary, spin-orbit coupling effects have been introduced. An understanding of the polarity of studied in the various electronic states is made possible by calculating the dipole moments. In addition, transition dipole moments were computed prior to the obtention of molecular parameters such as oscillator strength, Einstein coefficients, radiative probabilities and Franck–Condon factors. Overall good accuracy is observed.