Theoretical study of photodetachment processes of anionic boron clusters. I. Structure

Photo-induced electron detachment spectroscopy of anionic boron clusters, \documentclass[12pt]{minimal}\begin{document}${\rm B}_4^{-}$\end{document} B 4 − and \documentclass[12pt]{minimal}\begin{document}${\rm B}_5^{-}$\end{document} B 5 − , is theoretically investigated by performing electronic structure calculations and nuclear dynamics simulations. While the electronic potential energy surfaces ( \documentclass[12pt]{minimal}\begin{document}$\widetilde{X}^1A_{g}$\end{document} X ̃ 1 A g , \documentclass[12pt]{minimal}\begin{document}$\widetilde{a}^3B_{2u}$\end{document} a ̃ 3 B 2 u , \documentclass[12pt]{minimal}\begin{document}$\widetilde{b}^3B_{1u}$\end{document} b ̃ 3 B 1 u , \documentclass[12pt]{minimal}\begin{document}$\widetilde{A}^1B_{2u}$\end{document} A ̃ 1 B 2 u , \documentclass[12pt]{minimal}\begin{document}$\widetilde{c}^3B_{2g}$\end{document} c ̃ 3 B 2 g , and \documentclass[12pt]{minimal}\begin{document}$\widetilde{B}^1B_{2g}$\end{document} B ̃ 1 B 2 g of neutral B 4 and \documentclass[12pt]{minimal}\begin{document}$\widetilde{X}^2B_2$\end{document} X ̃ 2 B 2 , \documentclass[12pt]{minimal}\begin{document}$\widetilde{A}^2A_1$\end{document} A ̃ 2 A 1 , \documentclass[12pt]{minimal}\begin{document}$\widetilde{B}^2B_2$\end{document} B ̃ 2 B 2 , \documentclass[12pt]{minimal}\begin{document}$\widetilde{C}^2A_1$\end{document} C ̃ 2 A 1 , \documentclass[12pt]{minimal}\begin{document}$\widetilde{D}^2B_1$\end{document} D ̃ 2 B 1 , and \documentclass[12pt]{minimal}\begin{document}$\widetilde{E}^2A_1$\end{document} E ̃ 2 A 1 of neutral B 5 ) and their coupling surfaces are constructed in this paper, the details of the nuclear dynamics on these electronic states are presented in Paper II. Electronic structure calculations are carried out at the complete active space self-consistent field - multi-reference configuration interaction level of theory employing the correlation consistent polarized valance triple zeta basis set. Using the calculated electronic structure data suitable vibronic Hamiltonians are constructed utilizing a diabatic electronic basis and displacement coordinates of the normal vibrational modes. The theoretical results are discussed in relation to those recorded in recent experiments.