Orbital Dependent Exchange-Only Methods for Periodic Systems

TL;DR

This paper explores orbital-dependent exchange-only potentials with correct asymptotic behaviour for periodic systems, applying them to polymers and molecules, and compares their effectiveness with other methods in calculating electronic properties.

Contribution

It introduces the first application of these potentials to polymers and compares their performance with Hartree-Fock and LDA methods in periodic systems.

Findings

Correct long-range asymptotic behaviour of potentials

Band gap correction aligns with experimental values

Potential applications to polymers and molecules

Abstract

Various orbital-dependent exchange-only potentials are studied which exhibit correct long-range asymptotic behaviour. We present the first application of these potentials for polymers and by one of these potentials for molecules. Kohn-Sham type calculations have been carried out for polyethylene in order to make valuable comparison of these potentials with each other as well as with Hartree-Fock and exchange-only LDA methods. The Kohn-Sham band gap obtained with the optimized effective potetial method is corrected with the exchange contribution to the derivative discontinuity of the exchange-correlation potential. The corrected band gap obtained with the Slater's exchange potential is 9.7 eV close to the experiment.