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Why the generalized gradient approximation works and how to go beyond it
Author(s) -
Burke Kieron,
Perdew John P.,
Ernzerhof Matthias
Publication year - 1997
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1997)61:2<287::aid-qua11>3.0.co;2-9
Subject(s) - density functional theory , hybrid functional , local density approximation , simple (philosophy) , statistical physics , spin density , variety (cybernetics) , time dependent density functional theory , orbital free density functional theory , physics , quantum mechanics , chemistry , mathematics , condensed matter physics , statistics , philosophy , epistemology
Abstract The local spin density (LSD) approximation, while of only moderate accuracy, has proven extremely reliable over three decades of use. We argue that any gradient‐corrected functional should preserve the correct features of LSD even if the system under study contains no regions of small density gradient. The Perdew‐Wang 1991 (PW91) functional respects this condition, while, e.g., the Lee‐Yang‐Parr (LYP) correlation functional violates it. We extend this idea to the next generation of density functionals, those which incorporate exact exchange via the optimized effective potential (OEP), with a model in which the correlation hole is constructed from the exact exchange hole. The resulting exchange‐correlation hole is deeper and less diffuse than the exact exchange hole. We denote such a functional as “locally correlated Hartree‐Fock” and list a variety of conditions such a functional should satisfy. We demonstrate the promise of this approach with a crude simple model. © 1997 John Wiley & Sons, Inc.