H_2S_2的构型及其异构化的量子化学研究  

Quantum chemical study on the structures and isomerization of H_2S_2

作　　者：钮应喜[1] 殷春浩[1] 魏雪松[1] 吕海萍[1] 李泽彬[1] 

机构地区：[1]中国矿业大学理学院,徐州221008

出　　处：《原子与分子物理学报》2008年第1期74-78,共5页Journal of Atomic and Molecular Physics

基　　金：国家教育部留学人员实验室建设科研基金(2003.18);中国矿业大学优秀创新团队基金(2004ZCX012)

摘　　要：采用量子化学中的二阶微扰(MP2)方法,在6-311+G(3df,2p)水平上,利用Gaussian软件优化反应物,过渡态和生成物的几何结构,在相同水平上对反应物,过渡态和生成物进行了频率分析,同时完成了内禀反应坐标(IRC)分析.进而利用过渡态理论,计算了温度在300K时的H迁移异构化反应的速率常数.研究结果表明,H2S2的构型有两种,分别为:线型和分叉型,其中线型HSSH的能量较低,为稳定结构;平衡常数很小,为2.2×10-20,不利于平衡从线型向分叉型异构体转化,反之,分叉型向线型转化较容易,因此分叉型异构体长时间存在的可能性不大;另外,线型向分叉型异构体转化的活化焓较大为195.09kJ/mol,反应速率常数较小,仅为4.98×10-22s-1,因此该异构化反应不易进行,其逆反应较易进行.MP2 calculations of quantum chemical theory at the 6-311 ＋ G（3df,2p ） basis set level were used to optimize the reactants, transition states and products with Gaussian program, the corresponding vibrational analysis were calculated at the same level. The transition-state for the unimolecular isornerization was conformed by the intrinsic reaction coordinate （IRC） calculation. Rate constants of the isomerization reaction were evaluated at 300 K by the classical transition state theory. The results demonstrate that the structure of H2S2 had two structures： one was linear, the other was branched, the structure of the linear HSSH was stabler; The equilibrium constant was 2.2 ×10^-20 at 300 K. The calculated activation enthalpy for the isomerization process was 195.09 kJ/mol,the reaction rate was pretty slow （only 4.98 ×10^-22s^-1）. Thus, the isomerization reaction process was more difficult.

关 键 词：MP2 并构化 过渡态 H2S2 

分 类 号：O641[理学—物理化学]