Photodetachment spectroscopy of carbon doped anionic boron cluster, CB<inf>9</inf>^-: A theoretical study

Abstract

The photodetachment spectroscopy of CB9- is theoretically studied in this paper. Extensive ab initio quantum chemistry calculations are carried out to construct the potential energy surfaces of the electronic ground and excited states of CB9. With the aid of these calculated adiabatic electronic energies, a vibronic coupling model is developed in a diabatic electronic basis and in terms of normal coordinates of vibrational modes following the standard vibronic coupling theory originally developed by Köppel et al. (1984). Employing the developed diabatic electronic model, first principles nuclear dynamics study is carried out to calculate the vibronic structure of photodetachment bands of CB9-. A systematic study is performed to elucidate the impact of electronic nonadiabatic effects on the photodetachment bands. The vibronic structure of the latter is assigned in terms of excitation of vibrational modes and the results are compared with the experimental findings. The internal conversion dynamics through conical intersections of electronic states is examined by analyzing the time-dependent electronic populations. The theoretical results are found to be in good agreement with the experimental data. The detailed theoretical study carried out here unambiguously supports the prediction of the global minimum structure of CB9-.