Accurately predicting electron affinities with Koopmans spectral functionals*

Density functional theory (DFT) is a popular method for electronic-structure calculations. But while Kohn-Sham eigenvalues can loosely mirror experimental quasiparticle energies, there is formally no connection between the two (except for the HOMO in exact DFT). Furthermore, the presence of self-interaction errors in semi-local DFT can make those eigenvalues an even poorer proxy for quasiparticle energies [1].

This talk will discuss Koopmans spectral functionals, an efficient approach for recovering spectral properties in a beyond-DFT formulation at very little additional computational cost [2-4]. They have already been shown to lead to accurate molecular ionization potentials [5], and I will present the latest results, including accurate predictions of molecular electron affinities in the GW100 set [6].

[1] Cohen et al., Science, 321, 792 (2008).
[2] Dabo et al., Phys. Rev. B, 82, 115121 (2010).
[3] Borghi et al., Phys. Rev. B 90, 075135 (2014).
[4] Nguyen et al., Phys. Rev. X, 8, 021051 (2018).
[5] Colonna et al., J. Chem. Theory Comput., 15, 1905 (2019).
[6] van Setten et al., J. Chem. Theory Comput., 11, 5565 (2015).