All-electronGWmethods implemented in molecular orbital space: Ionization energy and electron affinity of conjugated molecules

Abstract

An efficient all-electron ${G}^{0}{W}^{0}$ method and a quasiparticle self-consistent $GW$ (QSGW) method for molecules are proposed in the molecular-orbital space with the full random-phase approximation. The convergence with the basis set is examined. As an application, the ionization energy and electron affinity of a series of conjugated molecules (up to 32 atoms) are calculated and compared to the 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 electron affinity. 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.