Rg-HX分子间势的精确从头计算研究  

High Level ab Initio Study of Intermolecular Potential for the Rg-HX Complexs

作　　者：张愚[1] 史鸿运[1] 王伟周[1] 

机构地区：[1]贵州大学化学系,贵阳550025

出　　处：《物理化学学报》2001年第11期1013-1020,共8页Acta Physico-Chimica Sinica

基　　金：贵州省教委及科委基金资助项目~~

摘　　要：在用非迭代的三重激发项来校正CCSD的CCSDT理论水平下,采用augccpVQZ基函数对HeHF的分子间势进行了系统的研究.结果表明:HeHF以线型结构存在.在极限基的情况下,复合物两种线型极小点结构HeHF和HeFH势阱深分别为46.614cm-1和25.026cm-1对应He原子到HF分子质心的距离Rm分别为0.3149nm和0.3012nm.讨论了不同的基函数和理论方法在研究此类弱束缚态复合物的分子间势时的可靠性及其对结果的影响,并研究了HF分子中H-F键长的改变对势能的影响同时也给出了势函数的解析形式.The potential energy surfaces of the ground state of the He-HF complex have been calculated at several levels of theory, including the single and double excitation coupled-cluster method with noniterative perturbation treatment of triple excitation CCSD(T). Calculations have been performed using the augmented correlation-consistent polarized quadruple zeta basis set(aug-cc-pVQZ). Using the complete basis set (CBS), the global minimum with a well depth of approximately 46. 614 cm(-1) has been found for the linear He-H-F geometry ( theta = 0 degrees) with the distance Rm between the He atom and the center of mass of the HF molecule equal to 0. 3149 run. In addition to the global minimum, there is a second minimum at R = 0. 3012 nm and theta = 180 degrees (a well depth of 25. 026 cm(-1)). The effects of the basis ' sets, H - F bond length and theoretical methods on the intermolecular potential were discussed and a simple analytic form employing 17 adjustable parameters for fitting to the calculated PES was given.

关 键 词：从头计算 分子间势 PES CBS 分子间相互作用力 氢卤酸 稀有气体 复合物 量子化学 

分 类 号：O641[理学—物理化学]