一种激发至六电子对的耦合簇方法：用于键断裂过程的公式推导和测试应用。

A coupled cluster approach with excitations up to six orbital pairs: the formulation and test applications for bond breaking processes.

机构信息

School of Chemistry and Chemical Engineering, Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute of Theoretical and Computational Chemistry, Nanjing University, Nanjing 210093, People's Republic of China.

出版信息

J Chem Phys. 2011 Jun 21;134(23):234104. doi: 10.1063/1.3600396.

DOI:10.1063/1.3600396

PMID:21702547

Abstract

The formalism of the coupled cluster (CC) method with excitations up to six orbital pairs (CC6P) and its illustrative applications are presented. By definition, CC6P includes connected excitations from full singles, doubles, triples, and partial quadruples, pentuples, and hextuples. CC6P and its approximate variants (CC6P-4, CC6P-5, and CC6P-6a) have the similar computational cost as the CC singles, doubles, and triples (CCSDT). They have been applied to investigate the potential energy surfaces for bond dissociation processes in four small molecules (F(2), H(2)O, N(2), and F(2)(+)). In comparison with full configuration interaction results, CC6P and its approximate variants are demonstrated to provide very accurate descriptions for the single-bond breaking process in F(2). While for multi-bond breaking processes, these methods provide considerable improvement over CCSDT.

摘要

本文介绍了最高激发至六电子对的耦合簇（CC）方法的形式体系及其应用实例。根据定义，CC6P 包括从全单、双、三到部分四、五和六重激发的连接激发。CC6P 及其近似变体（CC6P-4、CC6P-5 和 CC6P-6a）的计算成本与 CC 单、双和三重激发（CCSDT）相似。它们已被应用于研究四个小分子（F(2)、H(2)O、N(2)和 F(2)(+)）中键离解过程的势能面。与全组态相互作用结果相比，CC6P 及其近似变体被证明能够非常准确地描述 F(2)中的单键断裂过程。而对于多键断裂过程，这些方法相对于 CCSDT 提供了相当大的改进。