Fully Analytic G0W0 Nuclear Gradients

In this letter, we present the first fully analytic derivation and implementation of nuclear gradients for the G0W0 method. For this, we leverage the recently established connection between the G0W0 approach and equation-of-motion unitary coupled-cluster theory for charged excitations. Analytic gradients are obtained through the Lagrangian technique and are implemented and validated by comparison with finite-difference calculations. For G0W0, we examine the effect of the Tamm-Dancoff approximation for evaluating the screened Coulomb interaction. Finally, we compare G0W0 adiabatic ionization potential and electron affinities to wave function-based electronic structure methods and experimental values.