GW Approximation Coupled with Classical Fluctuating Charges and Dipoles.

We propose a novel multiscale QM/classical methodology based on the GW approximation combined with the fluctuating charges (FQ) and fluctuating charges and dipoles (FQFμ) force fields. The GW approximation is exploited to capture electron correlation effects, while FQ or FQFμ is used to model the mutual polarization effects between the quantum GW system and its surrounding environment in a multiscale fashion. The model is validated through test calculations of ionization potentials of aqueous phenol and applied to the Green Fluorescent Protein (GFP) chromophore (4-hydroxybenzylidene-1,2-dimethylimidazolinone─p-HDBI) in aqueous solution.