论文标题
Quasiparticle自一致的$ GW $ -Bethe-salpeter方程计算大型发色系统的计算
Quasiparticle Self-Consistent $GW$-Bethe-Salpeter equation calculations for large chromophoric systems
论文作者
论文摘要
$ GW $ -BETHE-SALPETER方程（BSE）方法有望计算分子系统的低洼激发态。到目前为止，它仅应用于相当小的分子，并且在对电子自能源的对角近似中，它取决于平均场的起点。我们在这里描述了自洽和起点独立的准粒子自洽（QS $ GW $） - BSE方法的实现，该方法适用于大分子的计算。我们在本文中表明，仅特征值的自隔离导致对叶绿素二聚体的某些激发态的不忠实描述，而QS $ GW $ -BSE垂直激发能（VEE）非常符合与气相中测量叶绿素单数和二聚体的光谱实验的一致性。另一方面，来自时间依赖的密度功能理论计算的Vees倾向于不同意实验值，并使用不同范围分隔的混合体（RSH）内核将VEE的VEES的变化高达0.5 eV。我们使用新的QS $ GW $ -BSE实现来计算光系统II（PSII）反应中心（RC）的六个发色团的最低激发能，其具有近2000个相关电子。使用超过11000（6000）个基础函数，可以在不到5（2）天的时间内完成计算一个单个现代计算节点。与以前的TD-DFT计算使用RSH内核对也不包括环境效应的模型计算，我们的QS $ GW $ -BSE计算仅在六聚体络合物的低能频谱中产生具有局部特征的状态。与RSH内核的较早工作表明，蛋白质环境有助于实验观察到的鸡际电荷转移。因此，未来的研究将需要将TD-DFT以外的相关效应与对环境静电学的明确处理相结合。
The $GW$-Bethe-Salpeter Equation (BSE) method is promising for calculating the low-lying excited states of molecular systems. So far, it has only been applied to rather small molecules, and in the commonly implemented diagonal approximations to the electronic self-energy it depends on a mean-field starting point. We describe here an implementation of the self-consistent and starting-point independent quasiparticle self-consistent (qs$GW$)-BSE approach which is suitable for calculations on large molecules. We herein show that eigenvalue-only self-consistency leads to an unfaithful description of certain excitonic states for Chlorophyll dimers while the qs$GW$-BSE vertical excitation energies (VEE) are in excellent agreement with spectroscopic experiments for Chlorophyll monomers and dimers measured in the gas phase. On the other hand, VEEs from time-dependent density functional theory calculations tend to disagree with experimental values and using different range-separated hybrid (RSH) kernels changes the VEEs by up to 0.5 eV. We use the new qs$GW$-BSE implementation to calculate the lowest excitation energies of the six chromophores of the photosystem II (PSII) reaction center (RC) with nearly 2000 correlated electrons. Using more than 11000 (6000) basis functions, the calculation could be completed in less than 5 (2) days one a single modern compute node. In agreement with previous TD-DFT calculations using RSH kernels on models that do also not include environment effects, our qs$GW$-BSE calculations only yield states with local character in the low-energy spectrum of the hexameric complex. Earlier work with RSH kernels has demonstrated that the protein environment facilitates the experimentally observed interchromophoric charge transfer. Therefore, future research will need to combine correlation effects beyond TD-DFT with an explicit treatment of environment electrostatics.
