HAsO_2异构体结构、相对稳定性与体系势能面

The Structures, Relative Stability, and Potential Energy Surface of HAsO_2 Isomers

在MP2/6-311+ +G（d,p）和 qcisd（T）/6-311+ +G（3df,2p）（单点）水平下计算得到了包括9个异构体和10个过渡态的HAsO2体系势能面.在势能面上,异构体cis-HOAso（El）的能量是最低的,其次是trans-HOAsO（E2）和HAsO（O）（C2V,E3）,能量分别比cis-HOAsO高13.35和192.74 kJ/mol.根据体系的势能面,异构体 E1,E3及cis-HOOAs（E6）,trans-HOOAs（E5）具有一定的动力学稳定性,在实验中应该可以观测到.AsH和O2反应的第一步产物将会异构化为具有较高动力学稳定性的异构体E3;而OH和AsO反应可直接生成El.计算结果与HPO2,HPS2,HNO2,HNS2等价电子相同的分子的势能面进行了比较.

The potential energy surface (PES) of HAsO2 system including nine isomers and ten transition states is predicated at MP2/6-311 + + G(d, p) and QCISD(T)/6-311 + + G(3df, 2p) (single-point) levels of theory. On the PES, cis-HOAsO(E1) is found to be thermodynamically the most stable isomer followed by trans-HOAsO(E2) and HAsO(O)( C-2V, E3) at 13.15 and 192.74 kJ/mol. Based on the PES, E1, E3, cis-HOOAs(E6) and trans-HOOAs(E5) are thermodynamically and kinetically stable isomers, and should be experimentally observable. The products in the first-step reaction of HAs with O-2 can isomerize into isomer E3 that has higher thermodynamical stability. The reaction of OH with AsO will directly lead to the formation of isomer E1. The comparison of the calculated results with the PESs Of HPO2, HPS2, HNO2, HNS2(analogs of HAsO2) is also made.