All-electron GW calculation for molecules: Ionization energy and electron affinity of conjugated molecules

TL;DR

This paper introduces efficient all-electron GW methods for molecules, demonstrating improved accuracy in ionization energy and electron affinity calculations over traditional methods, especially for conjugated molecules.

Contribution

The paper develops and applies all-electron G0W0 and QSGW methods in molecular orbital space with full RPA, showing enhanced agreement with experimental data.

Findings

QSGW improves G0W0 results

Both methods outperform Hartree-Fock and hybrid DFT

Accurate energy gaps and reduced self-interaction errors

Abstract

An efficient all-electron G$^0$W$^0$ method and a quasiparticle selfconsistent GW (QSGW) method for molecules are proposed in the molecular orbital space with the full random phase approximation. The convergence with basis set is examined. As an application, the ionization energy ($I$) and electron affinity ($A$) of a series of conjugated molecules (up to 32 atoms) are calculated and compared to experiment. The QSGW result improves the G$^0$W$^0$ result and both of them are in significantly better agreement with experimental data than those from Hartree-Fock (HF) and hybrid density functional calculations, especially for $A$. The nearly correct energy gap and suppressed self-interaction error by the HF exchange make our method a good candidate for investigating electronic and transport properties of molecular systems.