Theoretical prediction on HAlS+ and HSAl+ cations using multiconfiguration second‐order perturbation theory |
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Authors: | Wen‐Zuo Li Yu‐Wei Pei F‐F Geng Jian‐Bo Cheng Qing‐Zhong Li Bao‐An Gong |
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Institution: | The Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, People's Republic of China |
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Abstract: | Some low‐lying states of the HAlS+ and HSAl+ cations have been studied for the first time by large‐scale theoretical calculations using three methods: complete active space self‐consistent field (CASSCF), complete active second‐order perturbation theory (CASPT2), and density functional theory Becke's three‐parameter hybrid function with the nonlocal correlation of Lee–Yang–Parr (B3LYP) with the contracted atomic natural orbital (ANO‐L) and cc‐pVTZ basis sets. The geometries of all stationary points along the potential energy surfaces (PESs) were optimized at the CASSCF/ANO‐L and B3LYP/cc‐pVTZ levels. The ground and the first excited states of linear HAlS+ are predicted to be X2Π and A2Σ+ states, respectively. For the linear HSAl+ structure, the first excited state is A2Σ+. The X2Π state of linear HSAl+ is a second‐order saddle point, because it has two imaginary frequencies. Two bent global minima M1 and M2 were found along the 12A′ and 12A″ PESs, respectively. The CASPT2/ANO‐L potential energy curves of isomerization reactions were calculated as a function of HAlS bond angle. According to our calculations, the ground‐state HAlS+ is linear, whereas the ground‐state HSAl+ is bent. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011 |
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Keywords: | HAlS+ HSAl+ CASSCF CASPT2 potential energy curve |
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