Klawohn Sascha, Bahmann Hilke
Technische Universität Berlin, Institut für Chemie , Theoretische Chemie/Quantenchemie Sekretariat C7, Straße des 17. Juni 135 , 10623 Berlin , Germany.
Physical and Theoretical Chemistry , University of Saarland , 66123 Saarbrücken , Germany.
J Chem Theory Comput. 2020 Feb 11;16(2):953-963. doi: 10.1021/acs.jctc.9b01015. Epub 2020 Jan 21.
Building on the previously introduced concept of local range separation (LRS) [ Krukau , A. V. ; Scuseria , G. E. ; Perdew , J. P. ; Savin , A. Hybrid functionals with local range separation 2008 129 124103 ], we report the first self-consistent implementation of hybrid exchange functionals with a position-dependent range-separation parameter. The two-electron integrals emerging from long-range exact exchange are calculated seminumerically. This avoids formerly suggested approximations to the exact exchange part and paves the way for applications to larger and chemically relevant systems. Additionally, we investigate the role of short-range exchange in this LRS scheme by comparing the local density approximation and PBE-type functionals. We propose a semiempirical approach for the range-separation function based on common ingredients of semilocal exchange-correlation functionals. Four parameters are optimized to a small training set of atomization energies and barrier heights. In comparison with established hybrid and semilocal functionals, the LRS functional performs well for basic chemical properties. In addition, our best functional yields outer-valence spectra comparable to optimally tuned approaches.
基于先前引入的局域范围分离（LRS）概念[克鲁考，A. V.；斯库西亚，G. E.；佩德韦，J. P.；萨文，A. 具有局域范围分离的杂化泛函 2008 129 124103]，我们报告了具有位置依赖范围分离参数的杂化交换泛函的首个自洽实现。长程精确交换产生的双电子积分采用半数值方法计算。这避免了先前对精确交换部分所建议的近似，为应用于更大且具有化学相关性的体系铺平了道路。此外，我们通过比较局域密度近似和PBE型泛函，研究了短程交换在该LRS方案中的作用。我们基于半局域交换相关泛函的常见成分，提出了一种用于范围分离函数的半经验方法。四个参数针对一小套原子化能和势垒高度的训练集进行了优化。与已确立的杂化和半局域泛函相比，LRS泛函在基本化学性质方面表现良好。此外，我们最佳的泛函产生的外层价光谱与优化调整的方法相当。
