Apparent Surface Charge models (such as PCM, COSMO, and SMD 66 ) adopt a coarse-grained description of solvent molecules as a set of surrogate charges qs -screening charges on the tessellated chromophore molecular surface (s). In an oversimplified interpretation, those screening charges can be regarded as those partially or nearly completely -depending on the solvent optical and static dielectric constants -cancel out the electrostatic potential of the chromophore electron density on the surface ϕ