Kubas A
Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
J Chem Theory Comput. 2021 May 11;17(5):2917-2927. doi: 10.1021/acs.jctc.1c00126. Epub 2021 Apr 8.
The electronic coupling matrix element is an essential ingredient of most electron-transfer theories. depends on the overlap between donor and acceptor wave functions and is affected by the involved states' spin. We classify the spin-state effects into three categories: orbital occupation, spin-dependent electron density, and density delocalization. The orbital occupancy reflects the diverse chemical nature and reactivity of the spin states of interest. The effect of spin-dependent density is related to a more compact electron density cloud at lower spin states due to decreased exchange interactions between electrons. Density delocalization is strongly connected with the covalency concept that increases the spatial extent of the diabatic state's electron density in specific directions. We illustrate these effects with high-level calculations on model direct donor-acceptor systems relevant to metal oxide materials and biological electron transfer. Obtained results can be used to benchmark existing methods for calculations in complicated cases such as spin-crossover materials or antiferromagnetically coupled systems.
电子耦合矩阵元是大多数电子转移理论的基本要素。它取决于供体和受体波函数之间的重叠，并受所涉及状态的自旋影响。我们将自旋态效应分为三类：轨道占据、自旋相关电子密度和密度离域。轨道占有率反映了感兴趣的自旋态的不同化学性质和反应性。自旋相关密度的效应与较低自旋态下更紧凑的电子密度云有关，这是由于电子之间的交换相互作用减少。密度离域与共价性概念密切相关，共价性概念增加了绝热态电子密度在特定方向上的空间范围。我们通过对与金属氧化物材料和生物电子转移相关的模型直接供体-受体系统进行高水平计算来说明这些效应。所得结果可用于在自旋交叉材料或反铁磁耦合系统等复杂情况下对现有计算方法进行基准测试。
