HPOS体系异构体结构与稳定性

在MP2／6－311＋＋G(d,p)和QCISD（T）／6－311＋＋G（3df,2p)（单点）水 平下计算得到了HPOS体系势能面上18个异构体和25个过渡态及解离碎片等驻点，并 分析了这些异构体的结构及异构化过程，讨论了可能的解离方式。在得到的异构体 中，有8个异构体是动力学较稳定的，它们是dis-HOPS,trans-HOPS,trans-HSPO, cis-HSPO,HP(O)S(Cs),trans-HPSO,cis-HPSO和HP（O）S（C1）。这些异构体在实 验中应该可以观测到。理论研究表明，P与S原子较强的超价能力在降低异构体能量 ，提高异构体动力学稳定性方面起到了关键的作用。得到的计算结果与HPO2， HPS2，HNOS等价电子相同的体系进行了比较。

The Structures and Stability of HPOS Isomers

A singlet potential energy surface (PES) of HPOS system including eighteen isomers, twenty-five transition states and dissociation fragments has been investigated at MP2/6-311++G(d, p) and QCISD(T)/6-311++G(3df, 2p) (single-point) levels of theory. The structures and isomerizations of the optimized isomers are discussed, while their possible dissociation pathways are predicted. In all the optimized isomers, eight species, i.e., cis-HOPS, trans-HOPS, trans-HSPO, cis-HSPO, HP(O)S(C_s), trans-HPSO, cis-HPSO and HP(O)S(C_1), can be considered as kinetically stable isomers, and may be detected experimentally. The calculated results indicate that the stronger hypervalent capacities of P and S play an important role in decreasing the energy and increasing kinetic stability of isomers. The comparison among HPOS system and its analogs, HPO_2, HPS_2 and HNOS, is made.