含旋轨耦合的双电离和双电子亲和运动方程耦合簇方法

项目名称： 含旋轨耦合的双电离和双电子亲和运动方程耦合簇方法

项目编号： No.21473116

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 王繁

作者单位： 四川大学

项目金额： 90万元

中文摘要： 本项目中，我们计划发展含旋轨耦合的双电离与双电子亲和EOM-CCSD计算方法及计算程序，用以研究一些需考虑旋轨耦合效应的多参考态体系。在此基础上，我们还将考察旋轨耦合的近似处理方案以降低计算量，研究高阶激发的微扰计算方法以提高计算精度。这个方法适用于从一个闭壳层体系电离或者添加两个电子所能得到的电子态。由于在描述旋轨耦合作用上有较高精度，这个方法能用于旋轨耦合效应比较强的体系。与在自洽场计算中就考虑旋轨耦合作用的方法相比，在没有明显降低计算精度的情况下该方法的计算量更低；与多参考态方法相比，这个方法无需选择参考态或活性空间，使用起来更加简单。这个方法能用于研究含p区的重元素原子与分子体系、一些锕系离子与分子体系、自旋三重态分子的零场分裂以及自旋三重态和单重态之间的自旋禁阻反应等。

中文关键词： 电子结构；理论化学；电子激发态

英文摘要： In this project, we propose to develop computational method and program for double ionization and double electron-attachment based on equation-of-motion coupled-cluster theory at CCSD level to investigate multireference systems with spin-orbit coupling (SOC). In addition, approximate treatment on SOC will be developed to reduce computational effort without scarifying accuracy and higher level excitations will be included perturbatively to improve accuracy. This approach is suitable for those states that can be reached by removing or attaching two electrons from a closed-shell reference. Due to its high accuracy in describing SOC, it can be applied to systems with strong SOC effects. The present approach is computationally less demanding than approaches where SOC is already included at the SCF level. Furthermore, it can be used more easily since selecting references or active space is not required compared with other multireference approaches. This approach can be adopted for atoms or molecules containing heavy p-block elements, some actinide ions and molecules, zero field splitting of triplet molecules, as well as spin-forbidden reactions between singlet and triplet states.

英文关键词： electronic structure;theoretical chemistry;excited states