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

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 CH+ whose fundamental X-1 sigma(+) state lies 111.12nm above the corresponding X-2 Pi state of its neutral parent $ {\rm CH} $ CH 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 CH(+ )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.

Automated summary

By combining the MRCI-SD(T) method with the cc-pV6Z basis set, we are able to determine the potential energy curves of the CH+ molecular cation and calculate accurate spectroscopic constants. These results show good agreement with experimental and theoretical values, demonstrating the effectiveness of this method.