A Comprehensive Comparison of the IEFPCM and SS(V)PE Continuum Solvation Methods with the COSMO Approach

Dielectric continuum models are popular for modeling solvent effects in quantum chemical calculations. The polarizable continuum model (PCM) was originally published exploiting the exact dielectric boundary condition. This is nowadays called DPCM. The conductor-like screening model (COSMO) introduced a simplified and slightly empirical scaled conductor boundary condition, which turned out to reduce the errors resulting from outlying charge. This was implemented in PCM as CPCM. Later, the integral equation formalism (IEFPCM) and the formally identical SS(V)PE model of Chipman introduced a modified dielectric boundary condition combining the dielectric exactness of DPCM with the reduced outlying charge sensitivity of COSMO. In this paper, we demonstrate on two huge data sets of neutral and ionic solutes that no significant difference can be observed between the COSMO and IEFPCM, if the correct scaling factor is chosen for COSMO.