Fraiponts Mathias, Maes Wouter, Champagne Benoît
Laboratory of Theoretical Chemistry (LCT), Theoretical and Structural Physical Chemistry Unit, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium.
Design & Synthesis of Organic Semiconductors (DSOS), Hasselt University, Agoralaan 1, 3590 Diepenbeek, Belgium.
J Chem Theory Comput. 2024 Apr 9;20(7):2751-2760. doi: 10.1021/acs.jctc.3c01148. Epub 2024 Feb 26.
A novel approach for assessing the extent of electron displacement in optical transitions is proposed by implementing the Earth Mover's Distance (EMD) method, which quantifies the spatial dissimilarity between ground and excited state electron density distributions. In contrast to previous descriptors, this index provides a representative and intuitively understandable distance under a robust and computationally efficient scheme for all possible forms of locality, even in the most difficult to dissect topological cases. The theoretical differences among the existing indices and our method are first illustrated with the help of a simplified model system, followed by a benchmarking of several partial atomic charge models using experimentally relevant push-pull compounds with diverse symmetries. These same molecules are finally employed to further demonstrate the principal advantages of the EMD index and its capabilities in rationalizing charge transfer phenomena.
通过实施地球移动距离（EMD）方法，提出了一种评估光学跃迁中电子位移程度的新方法，该方法量化了基态和激发态电子密度分布之间的空间差异。与先前的描述符相比，该指标在稳健且计算高效的方案下，为所有可能形式的局部性提供了一个具有代表性且直观易懂的距离，即使在最难剖析的拓扑情况下也是如此。首先借助一个简化的模型系统来说明现有指标与我们方法之间的理论差异，随后使用具有不同对称性的实验相关推拉化合物对几种部分原子电荷模型进行基准测试。这些相同的分子最终被用于进一步证明EMD指标的主要优点及其在合理解释电荷转移现象方面的能力。
