Open AccessExact Second-Order Corrections and Accurate Quasiparticle Energy Calculations in Density Functional Theory
Author(s) -
Yuncai Mei,
Zehua Chen,
Weitao Yang
Publication year - 2021
Publication title -
the journal of physical chemistry letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.563
H-Index - 203
ISSN - 1948-7185
DOI - 10.1021/acs.jpclett.1c01962
Subject(s) - quasiparticle , atomic orbital , physics , photoexcitation , density functional theory , ionization , delocalized electron , ionization energy , ground state , quantum mechanics , scaling , order (exchange) , atomic physics , electron , computational physics , statistical physics , mathematics , excited state , geometry , ion , superconductivity , finance , economics
We develop a second-order correction to commonly used density functional approximations (DFAs) to eliminate the systematic delocalization error. The method, based on the previously developed global scaling correction (GSC), is an exact quadratic correction to the DFA for the fractional charge behavior and uses the analytical second derivatives of the total energy with respect to fractional occupation numbers of the canonical molecular orbitals. For small and medium-size molecules, this correction leads to ground-state orbital energies that are a highly accurate approximation to the corresponding quasiparticle energies. It provides excellent predictions of ionization potentials, electron affinities, photoemission spectrum, and photoexcitation energies beyond previous approximate second-order approaches, thus showing potential for broad applications in computational spectroscopy.