An approximate method, recently proposed to include in continuum solvation models the effects of electronic charge lying outside the solute cavity, has been adapted and implemented in the framework of the polarizable continuum model (PCM). This formulation exploits all the features already developed for the other PCM versions; it provides molecular free energies, gradients and second derivatives with respect to nuclear coordinates. The performances of this method have been tested in comparison with other PCM versions, in particular, we examined the reliability of this technique to reproduce actual volume charge distribution effects, compared to traditional procedures based on Gauss' Law. (C) 2001 American Institute of Physics.