An ab initio calculation of the vibronic energy levels of the X (2)Pi and 1 (2)Delta electronic states of C(2)P.

In the present study, the results of an ab initio calculation of the vibronic energy levels in the X (2)Pi and 1 (2)Delta electronic states of C(2)P are reported. This work is motivated by recent measurements carried out by [Sunahori et al. J. Chem. Phys. 128, 244311 (2008)]. The vertical electronic spectrum, excitation energies, bending potential curves, and spin-orbit constants for the title molecule are computed by means of the state-average complete active space self-consistent field and multireference configuration interaction approach. Vibronic energy levels of the X (2)Pi and 1 (2)Delta states are calculated with the help of a simple, effectively one-dimensional model. The results of the present study strongly support the analysis of experimental data by Sunahori et al. and offer reliable predictions for experimental searches for heretofore unobserved electronic states.