Theoretical prediction on HBeN~- and HNBe~- anions using multiconfiguration second-order perturbation theory

摘要

The HBeN~- and HNBe~- anions have been investigated for the first time using the CASSCF, CASPT2, and DFT/B3LYP methods with the contracted atomic natural orbital (ANO) and cc-pVTZ basis sets. The geometries of all stationary points along the potential energy surfaces were optimized at the CASSCF/ANO and B3LYP/cc-pVTZ levels. The ground and the first excited states of HBeN~- are predicted to be X~2∏ and A ~2∑~+ states, respectively. It was predicted that the ground state of HNBe~- is X~2∑~+ state. The A~2∏ state of HNBe~- has unique imaginary frequency. A bend local minimum M1 was found along the 1~2A″ potential energy surface and the A~2∏ state of HNBe~- should be the transition state of the isomerization reactions for M1 → M1. The CASPT2/ANO potential energy curves of isomerization reactions were calculated as a function of HBeN bond angle.