Ballester M Y, Varandas A J C
Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal.
Phys Chem Chem Phys. 2005 Jun 7;7(11):2305-17. doi: 10.1039/b500990a.
A global potential energy surface is reported for the ground electronic state of HSO2 by using the double many-body expansion (DMBE) method. It employs realistic DMBE functions previously reported from accurate ab initio calculations (in some cases, fine tuned to spectroscopic data) for the triatomic fragments, and four-body energy terms that were modelled by fitting novel ab initio FVCAS/AVTZ calculations for the tetratomic system. In some cases, FVCAS/AVDZ energies have been employed after being scaled to FVCAS/AVTZ ones. To assess the role of the dynamical correlation, exploratory single-point Rayleigh-Schrödinger perturbation calculations have also been conducted at one stationary point. All reported calculations are compared with previous ab initio results for the title system. The potential energy surface predicts HOSO to be the most stable configuration, in good agreement with other theoretical data available in the literature. In turn, the HSO2 isomer with H bonded to S is described as a local minimum, which is stable with respect to the H + SO2 dissociation asymptote.
通过使用双多体展开（DMBE）方法，报道了HSO₂基态的全局势能面。它采用了先前从精确的从头算计算（在某些情况下，根据光谱数据进行了微调）中报道的用于三原子片段的实际DMBE函数，以及通过对四原子系统的新颖从头算FVCAS/AVTZ计算进行拟合而建模的四体能量项。在某些情况下，FVCAS/AVDZ能量在按比例缩放到FVCAS/AVTZ能量后被采用。为了评估动态相关的作用，还在一个驻点进行了探索性的单点瑞利 - 薛定谔微扰计算。所有报道的计算都与之前关于该标题系统的从头算结果进行了比较。势能面预测HOSO是最稳定的构型，这与文献中其他可用的理论数据高度一致。反过来，H与S键合的HSO₂异构体被描述为一个局部最小值，相对于H + SO₂解离渐近线是稳定的。
