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arXiv · 2008.05057

The Fermi-Löwdin self-interaction correction for ionization energies of organic molecules

Santosh Adhikari·Biswajit Santra·Shiqi Ruan·Puskar Bhattarai·Niraj K. Nepal·Koblar A. Jackson·Adrienn Ruzsinszky
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Abstract

(Semi)-local density functional approximations (DFAs) suffer from self-interaction error (SIE). When the first ionization energy (IE) is computed as the negative of the highest-occupied orbital (HO) eigenvalue, DFAs notoriously underestimate them compared to quasi-particle calculations. The inaccuracy for the HO is attributed to SIE inherent in DFAs. We assessed the IE based on Perdew-Zunger self-interaction corrections on 14 small to moderate-sized organic molecules relevant in organic electronics and polymer donor materials. Though self-interaction corrected DFAs were found to significantly improve the IE relative to the uncorrected DFAs, they overestimate. However, when the self-interaction correction is interiorly scaled using a function of the iso-orbital indicator zσ, only the regions where SIE is significant get a correction. We discuss these approaches and show how these methods significantly improve the description of the HO eigenvalue for the organic molecules.

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Santosh Adhikari, Biswajit Santra, Shiqi Ruan, Puskar Bhattarai, Niraj K. Nepal, Koblar A. Jackson, Adrienn Ruzsinszky. 2020-08-12. The Fermi-Löwdin self-interaction correction for ionization energies of organic molecules. https://arxiv.org/abs/2008.05057

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