Solvated Charge Transfer States of Functionalized Anthracene and Tetracyanoethylene Dimers: A Computational Study Based on a Range Separated Hybrid Functional and Charge Constrained Self-Consistent Field with Switching Gaussian Polarized Continuum Models

We benchmark several protocols for evaluating the energies of excited charge transfer (CT) states of organic molecules dissolved in polar liquids. The protocols combine time-dependent density functional theory using range-separated hybrid functionals, constrained density functional theory, dispersion corrected functional, and a dielectric continuum model for representing the solvent. We compare the different protocols against well-established experimental measured charge transfer state energies in solvated dimers of functionalized anthracene and tetracyanoethylene. We find that using the range-separated hybrid functional for the charge-transfer state energies and the combination of constrained density functional theory with the recently improved switching Gaussian polarizable continuum model (PCM) provide good agreement with the experimental values of the solvated CT states. We also find that using dispersion corrected solvated geometries for the weakly coupled donor-acceptor dimers considered here leads to improved agreement with experimental measured values.