Fig. (a) Schematic depiction of the CF3(CF2)3SO3H molecule in a heterogeneous solvation environment, such that the acidic -SO3H group and the perfluorocarbon tail are embedding in media with different dielectric constants, ε1 and ε2, respectively. A solute cavity consisting of atom-centered spheres is indicated, whose whose boundary is denoted by Γ. Note that ε = 1 within the solute cavity (r ∈ Ω). (b) Depiction of the surface quadrature grid points used for PCM calculations. The size of each discretization point si is an indication of its contribution ai to the cavity surface area, as defined in eq. 10.