Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom.
J Chem Phys. 2021 Mar 28;154(12):124106. doi: 10.1063/5.0041233.
Delta-self-consistent field (ΔSCF) theory is a conceptually simple and computationally inexpensive method for finding excited states. Using the maximum overlap method to guide optimization of the excited state, ΔSCF has been shown to predict excitation energies with a level of accuracy that is competitive with, and sometimes better than, that of time-dependent density functional theory. Here, we benchmark ΔSCF on a larger set of molecules than has previously been considered, and, in particular, we examine the performance of ΔSCF in predicting transition dipole moments, the essential quantity for spectral intensities. A potential downfall for ΔSCF transition dipoles is origin dependence induced by the nonorthogonality of ΔSCF ground and excited states. We propose and test a simple correction for this problem, based on symmetric orthogonalization of the states, and demonstrate its use on bacteriochlorophyll structures sampled from the photosynthetic antenna in purple bacteria.
Delta-self-consistent field (ΔSCF) 理论是一种概念简单、计算成本低的寻找激发态的方法。通过使用最大重叠方法来指导激发态的优化，ΔSCF 已被证明可以预测激发能，其准确性可与、甚至优于时变密度泛函理论相媲美。在这里，我们使用比以前更大的分子集来对 ΔSCF 进行基准测试，特别是，我们研究了 ΔSCF 在预测跃迁偶极矩方面的性能，跃迁偶极矩是光谱强度的基本量。ΔSCF 跃迁偶极子的一个潜在缺陷是由 ΔSCF 基态和激发态的非正交性引起的原点依赖性。我们提出并测试了一种基于状态对称正交化的简单修正方法，并将其应用于从紫色细菌光合作用天线中采样的细菌叶绿素结构。
