Assessing the role of Hartree-Fock exchange, correlation energy and long range corrections in evaluating ionization potential, and electron affinity in density functional theory
Journal
Journal of Computational Chemistry
Journal Volume
38
Journal Issue
21
Pages
1844-1852
Date Issued
2017
Author(s)
Abstract
Accurate determination of ionization potentials (IPs), electron affinities (EAs), fundamental gaps (FGs), and HOMO, LUMO energy levels of organic molecules play an important role in modeling and predicting the efficiencies of organic photovoltaics, OLEDs etc. In this work, we investigate the effects of Hartree Fock (HF) Exchange, correlation energy, and long range corrections in predicting IP and EA in Hybrid Functionals. We observe increase in percentage of HF exchange results in increase of IPs and decrease in EAs. Contrary to the general expectations inclusion of both HF exchange and correlation energy (from the second order perturbation theory MP2) leads to poor prediction. Range separated Hybrid Functionals are found to be more reliable among various DFT Functionals investigated. DFT Functionals predict accurate IPs whereas post HF methods predict accurate EAs. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
Subjects
CCSD(T); density functional theory; electron affinity; fundamental gap; ionization potential
SDGs
Other Subjects
Electron affinity; Electron energy levels; Forecasting; Ionization; Ionization potential; Molecular physics; Perturbation techniques; Photovoltaic effects; CCSD; Correlation energy; Exchange and correlation; Fundamental gap; Hartree-Fock exchanges; Long-range corrections; Organic photovoltaics; Second order perturbation theory; Density functional theory; article; density functional theory; expectation; ionization; Ips; nonhuman; prediction; theoretical study
Type
journal article