Self-Consistent Field and Polarizable Continuum Model: A New Strategy of Solution for the Coupled Equations

We present a new strategy for the solution of the self-consistent field (SCF) equations when solvent effects are included by means of the polarizable continuum model (PCM). By exploiting the recently introduced variational formalism of the PCM (VPCM), we are able to recast the self-consistent reaction field problem as an energy functional of both electronic and polarization degrees of freedom. The variational minimization of such a functional leads to the free energy of the solvated molecule at a given geometry. In this contribution we describe an effective procedure and its implementation to achieve the solution of such a variational problem. Moreover, we present numerical evidence that the new approach is superior to the traditional one in terms of performance, especially when a relatively inexpensive semiempirical method is used to describe medium- and large-size solutes.