Accurate density functional prediction of molecular electron affinity with the scaling corrected Kohn–Sham frontier orbital energies

ABSTRACT

Electron affinity (EA) is the energy released when an additional electron is attached to an atom or a molecule. EA is a fundamental thermochemical property, and it is closely pertinent to other important properties such as electronegativity and hardness. However, accurate prediction of EA is difficult with density functional theory methods. The somewhat large error of the calculated EAs originates mainly from the intrinsic delocalisation error associated with the approximate exchange--correlation functional. In this work, we employ a previously developed non-empirical global scaling correction approach, which explicitly imposes the Perdew–Parr–Levy–Balduz condition to the approximate functional, and achieve a substantially improved accuracy for the calculated EAs. In our approach, the EA is given by the scaling corrected Kohn–Sham lowest unoccupied molecular orbital energy of the neutral molecule, without the need to carry out the self-consistent-field calculation for the anion.

KEYWORDS:

• Density functional theory
• scaling correction approach
• electron affinity
• Kohn–Sham frontier orbital energy
• orbital relaxation

Acknowledgments

Support from the Supercomputing Center of USTC is appreciated.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Support from the Ministry of Science and Technology of China [grant number   2016YFA0400900], [grant number  2016YFA0200600] (Xiao Zheng); the National Natural Science Foundation of China [grant number  21573202], [grant number  21233007] (Xiao Zheng); the Fundamental Research Funds for Chinese Central Universities [grant number  2340000074] (Xiao Zheng); the National Science Foundation [grant number CHE-1362927] (Weitao Yang) is appreciated.