title: Accurate Kohn-Sham ionization potentials from scaled-opposite-spin second-order optimized effective potential methods.
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.
authors.affiliation: Istituto Nanoscienze-CNR, Euromediterranean Center for Nanomaterial Modelling and Technology (ECMT), via Arnesano, Lecce, 73100.|Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, Torun, 87-100, Poland.|Center for Biomolecular Nanotechnologies @UNILE, Istituto Italiano Di Tecnologia, via Barsanti, Arnesano, I-73010, Italy.
authors.forename: Szymon
authors.initials: S
authors.lastname: Śmiga
authors.affiliation: Istituto Nanoscienze-CNR, Euromediterranean Center for Nanomaterial Modelling and Technology (ECMT), via Arnesano, Lecce, 73100.|Center for Biomolecular Nanotechnologies @UNILE, Istituto Italiano Di Tecnologia, via Barsanti, Arnesano, I-73010, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Della Sala
authors.affiliation: Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, Torun, 87-100, Poland.
authors.forename: Adam
authors.initials: A
authors.lastname: Buksztel
authors.affiliation: Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, Torun, 87-100, Poland.
authors.forename: Ireneusz
authors.initials: I
authors.lastname: Grabowski
authors.affiliation: Istituto Nanoscienze-CNR, Euromediterranean Center for Nanomaterial Modelling and Technology (ECMT), via Arnesano, Lecce, 73100.|Center for Biomolecular Nanotechnologies @UNILE, Istituto Italiano Di Tecnologia, via Barsanti, Arnesano, I-73010, Italy.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Fabiano
keywords: ionization potential; optimized effective potential method; spin component scaled method