Accurate Kohn-Sham ionization potentials from scaled-opposite-spin second-order optimized effective potential methods

Szymon Śmiga; Fabio Della Sala; Adam Buksztel; Ireneusz Grabowski; Eduardo Fabiano

doi:10.1002/jcc.24436

Accurate Kohn-Sham ionization potentials from scaled-opposite-spin second-order optimized effective potential methods

J Comput Chem. 2016 Aug 15;37(22):2081-90. doi: 10.1002/jcc.24436. Epub 2016 Jun 30.

Authors

Szymon Śmiga^{1

2

3}, Fabio Della Sala^{1

3}, Adam Buksztel², Ireneusz Grabowski², Eduardo Fabiano^{1

3}

Affiliations

¹ Istituto Nanoscienze-CNR, Euromediterranean Center for Nanomaterial Modelling and Technology (ECMT), via Arnesano, Lecce, 73100.
² Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, Torun, 87-100, Poland.
³ Center for Biomolecular Nanotechnologies @UNILE, Istituto Italiano Di Tecnologia, via Barsanti, Arnesano, I-73010, Italy.

PMID: 27357413
DOI: 10.1002/jcc.24436

Abstract

One important property of Kohn-Sham (KS) density functional theory is the exact equality of the energy of the highest occupied KS orbital (HOMO) with the negative ionization potential of the system. This exact feature is out of reach for standard density-dependent semilocal functionals. Conversely, accurate results can be obtained using orbital-dependent functionals in the optimized effective potential (OEP) approach. In this article, we investigate the performance, in this context, of some advanced OEP methods, with special emphasis on the recently proposed scaled-opposite-spin OEP functional. Moreover, we analyze the impact of the so-called HOMO condition on the final quality of the HOMO energy. Results are compared to reference data obtained at the CCSD(T) level of theory. © 2016 Wiley Periodicals, Inc.

Keywords: ionization potential; optimized effective potential method; spin component scaled method.

Publication types

Research Support, Non-U.S. Gov't