Ekesan Solen, Lin Damian Y, Herzfeld Judith
Department of Chemistry, Brandeis University , 415 South Street MS#015, Waltham Massachusetts 02453, United States.
J Phys Chem B. 2016 Jul 7;120(26):6264-9. doi: 10.1021/acs.jpcb.6b02576. Epub 2016 Jun 1.
The past decade has seen the first attempts at quantifying a semiclassical description of electrons in molecules. The challenge in this endeavor is to find potentials for electron interactions that adequately capture quantum effects. As has been the case for density functionals, the challenge is particularly great for the effects that follow from the requirement for wave function antisymmetry. Here we extend our empirical inquiry into effective potentials, from prior work on the monatomic atoms and ions of nonmetals, to diatomic molecules and ions formed by these elements. Newly adjusted and trained for the longer distances relevant to diatomics, pairwise potentials are able to fit the bond orders and magnetic properties of homonuclear species. These potentials are then found to do an excellent job of predicting the magnetism of heteronuclear species. In these molecules the predicted distribution of electrons also correctly reflects increasing ionic character with increasing difference in the electronegativities of the participating atoms. The distinctive features of the current potential are discussed, along with issues calling for further improvements.
在过去十年中，人们首次尝试对分子中电子的半经典描述进行量化。这项工作面临的挑战是找到能够充分捕捉量子效应的电子相互作用势。正如密度泛函的情况一样，对于源于波函数反对称性要求的效应，挑战尤为巨大。在这里，我们将对有效势的实证研究从之前关于非金属单原子和离子的工作扩展到由这些元素形成的双原子分子和离子。针对与双原子相关的更长距离进行了新的调整和训练，成对势能够拟合同核物种的键级和磁性。然后发现这些势在预测异核物种的磁性方面表现出色。在这些分子中，预测的电子分布也正确地反映了随着参与原子电负性差异的增加，离子性增强的情况。我们讨论了当前势的独特特征，以及需要进一步改进的问题。
