Cookies

We use cookies to ensure that we give you the best experience on our website. You can change your cookie settings at any time. Otherwise, we'll assume you're OK to continue.

Durham University

Research & business

View Profile

Publication details for Prof. David J. Tozer

Vibert, Christopher P. & Tozer, David J. (2019). Simple DFT Scheme for Estimating Negative Electron Affinities. Journal of Chemical Theory and Computation 15(1): 241-248.

Author(s) from Durham

Abstract

A simple density functional theory (DFT) scheme is proposed for estimating negative vertical electron affinities of neutral systems, based on a consideration of the integer discontinuity and density scaling homogeneity. The key feature is the derivation of two system-dependent exchange-correlation functionals, one appropriate for the electron deficient side of the integer and one appropriate for the electron abundant side. The electron affinity is evaluated as a linear combination of frontier orbital energies from self-consistent Kohn–Sham calculations on the neutral system using these functionals. For two assessments comprising a total of 43 molecules, the scheme provides electron affinities that are in good agreement with experimental values and which are an improvement over those from the DFT method of Tozer and De Proft [ J. Phys. Chem. A 2005, 109, 8923]. The scheme is trivial to implement in any Kohn–Sham program, and the computational cost is that of a series of generalized gradient approximation Kohn–Sham calculations. More generally, the study provides a prescription for performing low-cost, self-consistent Kohn–Sham calculations that yield frontier orbital energies that approximately satisfy the appropriate Koopmans conditions, without the need for exact exchange.