Coupled-cluster theory based upon the fragment molecular-orbital method
Coupled-cluster theory based upon the fragment molecular-orbital method
复制标题
DOI：
10.1063/1.2007588
复制
发表时间：
2005-10-01
影响因子：
4.4
通讯作者：
Kitaura, K
中科院分区：
文献类型：
--
作者：
Fedorov, DG;Kitaura, K
将碎片分子轨道(FMO)方法与单参考耦合团簇(CC)理论相结合。所开发的方法(FMO-CC)被应用于CCSD和CCSD(T)理论水平，对于cc-pVnZ基组(n=D，T，Q)到水簇合物和甘氨酸低聚物(对于给定体系，使用尽可能大的基组，最多32个分子/残基)。详细讨论了二体和三体FMO-CC的计算结果，重点讨论了基组依赖和三体效应。发展了基于碎片间距离的二体和三体近似，并仔细确定了适合其准确应用的值。对于二体FMO-CC方法和三体FMO-CC方法，恢复相关能量的误差分别为几百万哈特里和亚毫哈特里。在最大的计算中，我们能够用cc-pVQZ基组(3680个基函数)计算(H2O)(32)和用cc-VDZ基组(712个关联电子)计算(Gly)(32)。FMO-CC使用两层并行方案的上层并行。证明了二体FMO-CC方法的计算尺度是近线性的。作为计时的一个例子，在8节点3.2-GHz奔腾4集群上，使用cc-pVDZ计算(H2O)(32)的CCSD(T)花费了13分钟。(C)2005年美国物理研究所。
The fragment molecular-orbital (FMO) method was combined with the single-reference coupled-cluster (CC) theory. The developed method (FMO-CC) was applied at the CCSD and CCSD(T) levels of theory, for the cc-pVnZ family of basis sets (n=D,T,Q) to water clusters and glycine oligomers (up to 32 molecules/residues using as large basis sets as possible for the given system). The two- and three-body FMO-CC results are discussed at length, with emphasis on the basis-set dependence and three-body effects. Two- and three-body approximations based on interfragment distances were developed and the values appropriate for their accurate application carefully determined. The error in recovering the correlation energy was several millihartree for the two-body FMO-CC method and in the submillihartree range for the three-body FMO-CC method. In the largest calculations, we were able to perform the CCSD(T) calculations of (H2O)(32) with the cc-pVQZ basis set (3680 basis functions) and (GLY)(32) with the cc-VDZ basis set (712 correlated electrons). FMO-CC was parallelized using the upper level of the two-layer parallelization scheme. The computational scaling of the two-body FMO-CC method was demonstrated to be nearly linear. As an example of timings, CCSD(T) calculations of (H2O)(32) with cc-pVDZ took 13 min on an eight node 3.2-GHz Pentium4 cluster. (c) 2005 American Institute of Physics.