Accurate calculations on 12 Λ-S and 28 ? states of BN~+ cation: Potential energy curves, spectroscopic parameters and spin-orbit coupling

摘要

The potential energy curves (PECs) of 28 Xstates generated from the 12 states (X~4Σ~-, 1~2∏, 1~2Σ~-, 1~2?, 1~2Σ~+, 2~2∏, A~4∏, B~4Σ~-, 3~2∏, 1~6Σ~-, 2~2Σ~- and 16~∏) of the BN~+ cation are studied for the first time for internuclear separations from about 0.1 to 1.0 nm using an ab initio quantum chemical method. All the K-S states correlate to the first four dissociation channels. The 1~6Σ~-, 3~2∏ and A~4∏ states are found to be the inverted ones. The 1~2Σ~+, 2~2∏, 3~2∏ and 2~2Σ~- states are found to possess the double well. The PECs are calculated by the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson correction. Core-valence correlation correction is included by a cc-pCV5Z basis set. Scalar relativistic correction is calculated by the third-order Douglas-Kroll Hamiltonian approximation at the level of a cc-pV5Z basis set. The convergent behavior of present calculations is discussed with respect to the basis set and level of theory. The spin-orbit coupling is accounted for by the state interaction approach with the Breit-Pauli Hamiltonian using the all-electron ccpCV5Z basis set. All the PECs are extrapolated to the complete basis set limit. The spectroscopic parameters are obtained, and the vibrational properties of 1~2Σ~+, 22∏, 3~2∏ and 2~2Σ~- states are evaluated. Analyses demonstrate that the spectroscopic parameters reported here can be expected to be reliably predicted ones. The conclusion is gained that the effect of spin-orbit coupling on the spectroscopic parameters are not obvious almost for all the K-S states involved in the present paper.