Kohut Sviataslau V, Polgar Alexander M, Staroverov Viktor N
Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada.
Phys Chem Chem Phys. 2016 Aug 21;18(31):20938-44. doi: 10.1039/c6cp00878j. Epub 2016 Mar 17.
The exact exchange-correlation potential of a stretched heteronuclear diatomic molecule exhibits a localized upshift in the region around the more electronegative atom; by this device the Kohn-Sham scheme ensures that the molecule dissociates into neutral atoms. Baerends and co-workers showed earlier that the upshift originates in the response part of the exchange-correlation potential. We describe a reliable numerical method for constructing the response potential of a given many-electron system and report accurate plots of this quantity. We also demonstrate that the step feature itself can be obtained directly from the interacting wavefunction of the system by computing the so-called average local electron energy. These findings illustrate in previously unavailable detail the mechanism of the formation of the upshift and the role played by static correlation in this process.
拉伸的异核双原子分子的精确交换关联势在电负性更强的原子周围区域呈现出局部上移；通过这种方式，科恩-沈（Kohn-Sham）方法确保分子解离为中性原子。贝伦兹（Baerends）及其同事早些时候表明，这种上移源于交换关联势的响应部分。我们描述了一种用于构建给定多电子系统响应势的可靠数值方法，并报告了该量的精确绘图。我们还证明，通过计算所谓的平均局部电子能量，可以直接从系统的相互作用波函数获得阶跃特征本身。这些发现以前所未有的细节说明了上移的形成机制以及静态关联在此过程中所起的作用。
