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Abstract

Many-body perturbation theory in theGW approximation is a useful method for describing electronic properties
associated with charged excitations. A hierarchy of GW methods exists, starting from non-self-consistent G0W0,
through partial self-consistency in the eigenvalues and in the Green’s function (scGW0), to fully self-consistent
GW (scGW). Here, we assess the performance of these methods for benzene, pyridine, and the diazines. The
quasiparticle spectra are compared to photoemission spectroscopy (PES) experimentswith respect to allmeasured
particle removal energies and the ordering of the frontier orbitals. We find that the accuracy of the calculated
spectra does not match the expectations based on their level of self-consistency. In particular, for certain starting
points G0W0 and scGW0 provide spectra in better agreement with the PES than scGW.