Density matrix renormalization group (DMRG) method as a common tool for large active-space CASSCF/CASPT2 calculations
Density matrix renormalization group (DMRG) method as a common tool for large active-space CASSCF/CASPT2 calculations
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DOI：
10.1063/1.4976644
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发表时间：
2017-03
影响因子：
4.4
通讯作者：
N. Nakatani;Sheng Guo
中科院分区：
文献类型：
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作者：
N. Nakatani;Sheng Guo
本文描述了密度矩阵重整化群（DMRG）方法和完全活性空间自洽场（CASSCF）方法之间的接口及其解析梯度，以及二阶微扰理论（CASPT 2）方法的扩展。这种接口允许很容易地执行大型活动空间多参考计算。该接口及其扩展都是在约化密度矩阵（RDM）方面实现的，该约化密度矩阵可以通过DMRG扫描算法有效地计算。我们还提出了基准测试结果表明，在实践中，DMRG-CASSCF计算规模与活动空间的大小在一个多项式的方式在准一维系统的情况下。利用DMRG-CASSCF分析梯度对双核铁硫簇合物进行了几何优化，结果表明，与小活性空间计算结果相比，硫的价p轨道和铁的双壳层d轨道的引入导致了不可忽略的几何变化。
This paper describes an interface between the density matrix renormalization group (DMRG) method and the complete active-space self-consistent field (CASSCF) method and its analytical gradient, as well as an extension to the second-order perturbation theory (CASPT2) method. This interfacing allows large active-space multi-reference computations to be easily performed. The interface and its extension are both implemented in terms of reduced density matrices (RDMs) which can be efficiently computed via the DMRG sweep algorithm. We also present benchmark results showing that, in practice, the DMRG-CASSCF calculations scale with active-space size in a polynomial manner in the case of quasi-1D systems. Geometry optimization of a binuclear iron-sulfur cluster using the DMRG-CASSCF analytical gradient is demonstrated, indicating that the inclusion of the valence p-orbitals of sulfur and double-shell d-orbitals of iron lead to non-negligible changes in the geometry compared to the results of small active-space ca...