Estimating the accuracy of pseudopotential based GW method at different levels of self consistency using Gaussian orbitals.

Many body perturbation theory provides an efficient and qualitatively cheap approach for estimating spectroscopic properties and charged excitation energies in solids and molecules. In this work we present the finite temperature GW method, which is one of the simplest approximations to the self-energy, at different levels of self consistency. In particular, we study the one shot G₀W₀, quasiparticle self consistent GW (qpGW) and fully self consistent GW (scGW) approaches. We assess the accuracy of commonly used pseudopotential based GW methods by comparing them to the all electron spin free X2C based GW approach which captures scalar relativistic effects efficiently. We present data showing that the use of ECP gives relatively good results for DFT while for correlated calculations, the errors are larger compared to the all electron calculations.