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arXiv 2104.02587physics.chem-ph
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选择组态相互作用方法中的轨道优化

Orbital Optimization in Selected Configuration Interaction Methods

Yuan Yao, C. J. Umrigar

摘要:

研究了几种选择组态相互作用加微扰理论(SCI+PT)方法中的轨道优化方法,并利用半随机热浴组态相互作用(SHCI)方法对三个分子的基态和激发态进行了测试.讨论了SCI中轨道优化问题与完全主动空间自洽场(CASSCF)中轨道优化问题的相似之处和不同之处。这些方法从自然轨道出发,根据它们如何处理组态相互作用(CI)系数和轨道参数之间的耦合,分为三类优化方法,即非耦合,完全耦合和准完全耦合方法。我们证明,考虑耦合是至关重要的快速收敛,并建议两个准完全耦合的方法,这样的应用程序:加速对角牛顿和Broyden-Fletcher-Goldfarb-Shanno(BFGS)。

英文摘要:

We study several approaches to orbital optimization in selected configuration interaction plus perturbation theory (SCI+PT) methods, and test them on the ground and excited states of three molecules using the semistochastic heatbath configuration interaction (SHCI) method. We discuss the ways in which the orbital optimization problem in SCI resembles and differs from that in complete active space self-consistent field (CASSCF). Starting from natural orbitals, these approaches divide into three classes of optimization methods according to how they treat coupling between configuration interaction (CI) coefficients and orbital parameters, namely uncoupled, fully coupled, and quasi-fully coupled methods. We demonstrate that taking the coupling into account is crucial for fast convergence and recommend two quasi-fully coupled methods for such applications: accelerated diagonal Newton and Broyden-Fletcher-Goldfarb-Shanno (BFGS).

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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