Self-Consistent Implementation of Hybrid Functionals with Local Range Separation.

Abstract

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 J. Chem. Phys. 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.