CASPT2 study on low‐lying states of HBN and HNB radicals

Abstract

ABSTRACT:In this study, some low-lying states of the HBN and HNB radicals have been studied using multiconfiguration second-order perturbation theory. The geometries of all stationary points along the potential energy surfaces (PESs) were optimized at the CASPT2/cc-pVQZ level. The ground and the first excited states of HBN were predicted to be X 2 ⌸ and A 2 ⌺ ϩ states, respectively. It was predicted that the ground state of HNB is X 2 ⌺ ϩ state. The A 2 ⌸ state of HNB has unique imaginary frequency, which was different from the previously published results. A bending local minimum M1 was found for the first time along the 1 2 AЉ PES, and the A 2 ⌸ state of HNB should be the transition state of the isomerization reactions for M1 7 M1. The CASPT2/ANO potential energy curves (PECs) of isomerization reactions for HBN 7 HNB were calculated as a function of HBN bond angle. By comparing the CASPT2 and CASSCF calculated results, we concluded that the influence of the dynamic electron correlation on HBN 7 HNB system is not large.

CASPT2 study on low‐lying states of HMgO and HOMg

“…, HBN $ HNB [10], and HAlO þ $ HOAl þ [11] by using CASSCF [12] and multiconfiguration second-order perturbation theory (CASPT2) [13,14] methods and got some new conclusions that were different from previously published results. The calculations [7][8][9][10][11] showed the importance of using multiconfiguration-based methods in the study on the excited states of such open shell systems.…”