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.
J Chem Phys. 2010 Dec 21;133(23):234106. doi: 10.1063/1.3518100.
An implementation of the coupled cluster (CC) singles, doubles, and a hybrid treatment of connected triples [denoted as CCSD(T)-h], based on the unrestricted Hartree-Fock (UHF) reference, is presented. Based on the spin-integrated formulation, we have developed a computer program to achieve the automatic derivation and implementation of the CCSD(T)-h approach. The CCSD(T)-h approach computationally scales as the seventh power of the system size, and is affordable for many medium-sized systems. The present approach has been applied to study the equilibrium geometries and harmonic vibrational frequencies in a number of open-shell diatomic molecules and bond breaking potential energy profiles in several open-shell molecules, including CH(3), NH(2), and SiH(2). For all systems under study, the overall performance of the UHF-based CCSD(T)-h approach is very close to that of the corresponding CCSDT (CC singles, doubles, and triples), and much better than that of the UHF-based CCSD(T) (CC singles, doubles, and perturbative triples).
本文介绍了一种基于非限制哈特ree-fock（UHF）基准的耦合簇（CC）单重态、双重态和三重态连接混合处理（记为 CCSD(T)-h）的实现。基于自旋积分公式，我们开发了一个计算机程序，实现 CCSD(T)-h 方法的自动推导和实现。CCSD(T)-h 方法的计算规模为系统大小的七次方，对于许多中型系统来说是可以承受的。本方法已应用于研究若干开壳层双原子分子的平衡几何形状和简正振动频率，以及若干开壳层分子的键断裂势能曲线，包括 CH(3)、NH(2)和 SiH(2)。对于所有研究的系统，基于 UHF 的 CCSD(T)-h 方法的整体性能非常接近相应的 CCSDT（CC 单重态、双重态和三重态），并且优于基于 UHF 的 CCSD(T)（CC 单重态、双重态和微扰三重态）。
Zotero 插件