CASPT2 study on low-lying states of HBS⁺ and HSB⁺ cations

Abstract

Some low-lying states of the nine-valence-electron systems HBS⁺ and HSB⁺ cations have been studied by large-scale theoretical calculations using three methods CASSCF, CASPT2, and DFT B3LYP with the contracted atomic natural orbital and cc-pVTZ basis sets. The geometries of all stationary points along the potential energy surfaces were optimized and the energies were calculated. The potential energy curves of isomerization reactions between HBS⁺ and HSB⁺ were calculated as a function of HBS bond angle. The calculated results indicated that the ground-state HBS⁺ is linear, while the ground-state HSB⁺ is bent, which is in contradiction to Walsh's rules predicting linear structures for the HXY systems containing 10 or less valency electrons.

Keywords:

• HBS⁺
• HSB⁺
• CASSCF
• CASPT2

Acknowledgements

This research was supported by the National Natural Science Foundation Committee of China (No. 21103145), the Natural Science Foundation of Shandong Province (No. ZR2009BQ006) and the Fund for Doctor of Yantai University (No. HY05B30). Professor Cheng acknowledges support by the Open fund (SKLSSM200909) of the State Key Laboratory of Supramolecular Structure and Materials, Jilin University.