Institute of Theoretical Solid State Physics, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straße 1, 76131 Karlsruhe, Germany.
J Chem Theory Comput. 2023 Jun 13;19(11):3131-3145. doi: 10.1021/acs.jctc.3c00156. Epub 2023 May 15.
The applicability of reduced scaling algorithms based on auxiliary subspace methods for the correlation energy from the random phase approximation (RPA) as well as the correlation part of the self-energy obtained from the method is outlined for time-reversal symmetry breaking Kohn-Sham (KS) references. The updated algorithms allow for an efficient evaluation of RPA energies and quasiparticle energies for molecular systems with KS references that break time-reversal symmetry. The latter occur, for example, in magnetic fields. Furthermore, KS references for relativistic open-shell molecules also break time-reversal symmetry due to the single determinant ansatz used. Errors of the updated reduced-scaling algorithms are shown to be negligible compared to reference implementations, while the overall computational scaling is reduced by 2 orders of magnitude. Ionization energies obtained from the approximation are shown to be robust even for the electronically complicated group of trivalent lanthanoid ions. Starting from quasiparticle energies, it is subsequently shown that light-matter interactions of these systems can be calculated using the Bethe-Salpeter equation (BSE). Using the combined -BSE method, the absorption and emission spectra of a molecular europium(III) complex can be obtained including spin-orbit coupling.
对于时间反演对称性破缺的 Kohn-Sham（KS）参考，概述了基于辅助子空间方法的缩减标度算法在关联能量的随机相位近似（RPA）以及从方法获得的自能关联部分的适用性。更新后的算法允许对具有时间反演对称性破缺的 KS 参考的分子系统的 RPA 能量和准粒子能量进行有效评估。例如，在磁场中会出现这种情况。此外，由于使用了单行列式假设，用于相对论开壳分子的 KS 参考也破坏了时间反演对称性。与参考实现相比，更新的缩减标度算法的误差可以忽略不计，而整体计算规模则降低了 2 个数量级。即使对于电子结构复杂的三价镧系离子群，从方法获得的电离能也被证明是稳健的。从准粒子能量出发，随后可以使用 Bethe-Salpeter 方程（BSE）来计算这些系统的光物质相互作用。使用组合的 -BSE 方法，可以获得包括自旋轨道耦合在内的分子铕（III）配合物的吸收和发射光谱。
