Quantitative Molecular Orbital Energies within a $G_0W_0$ Approximation
Abstract
Using many-body perturbation theory within the approximation, we explore routes for computing the ionization potential (IP), electron affinity (EA), and fundamental gap of three gas-phase molecules -- benzene, thiophene, and (1,4) diamino-benzene -- and compare with experiments. We examine the dependence of the IP on the number of unoccupied states used to build the dielectric function and the self energy, as well as the dielectric function plane-wave cutoff. We find that with an effective completion strategy for approximating the unoccupied subspace, and a converged dielectric function kinetic energy cutoff, the computed IPs and EAs are in excellent quantitative agreement with available experiment (within 0.2 eV), indicating that a one-shot approach can be very accurate for calculating addition/removal energies of small organic molecules. Our results indicate that a sufficient dielectric function kinetic energy cutoff may be the limiting step for a wide application of to larger organic systems.
Cite
@article{arxiv.1204.0509,
title = {Quantitative Molecular Orbital Energies within a $G_0W_0$ Approximation},
author = {Sahar Sharifzadeh and Isaac Tamblyn and Peter Doak and Pierre T. Darancet and Jeffrey B. Neaton},
journal= {arXiv preprint arXiv:1204.0509},
year = {2012}
}