Hybrid density functionals with proper exact exchange

Hybrid density functionals have the best overall performance among standard density func-tional approximations (DFA). According to their original design, hybrid DFAs are supposedto use the exact exchange (EXX). However, when hybrid functionals were originally intro-duced, there was no simple method to compute EXX, so all of their practical implementationsstarted using the Hartree–Fock exchange (HFX), which can be computed easily and is simi-lar to but distinct from EXX. Recent development of an efficient method for computing EXXmade it possible to implement hybrid functionals in line with their original definition. Weimplemented EXX in the PBE0 functional and compared its performance with that of HFX.We found that using EXX in PBE0 improves the standard enthalpies of formation, and thisimprovement increases with the size of the basis set and the size of the system. The max-imum improvement in standard enthalpies of formation of the G3-3 test set is 0.4 kcal/molwhen using 6-311++G(3df,3pd) basis set. For a hybrid density functional, the difference in theground-state energies computed using EXX and HFX depends quadratically on the percentageof EXX in the functional. We have also developed a method to generate the exact remainderexchange-correlation potential of the generalized Kohn–Sham DFT.

Name thesis:degree_name

M Sc

Discipline thesis:degree_discipline

Chemistry

Grantor dc:publisher

The University of Western Ontario

Year dc:date.issued

2020

Author dc:creator

• Ye, Liyuan

Advisor dc:contributor.advisor

• Viktor N. Staroverov

Language dc:language.iso

en_ca

Handle dc:identifier.uri

https://hdl.handle.net/20.500.14721/30775

OAI identifier oai:identifier

oai:uwo.scholaris.ca:20.500.14721/30775