Continuum solvation models: A new approach to the problem of solute's charge distribution and cavity boundaries

In continuum solvation models the definition of a cavity that embeds the solute molecule leads to problems related to the portion of solute's electronic charge lying outside its boundaries (charge tails). The correction strategies developed so far can be shown to work insufficiently, since they only correct the global charge defect, but lead to considerable local errors. The present paper will be focused on the theoretical and technical aspects of this problem, and it will present in detail a new method which allows a very refined treatment of solute's charge tails in the outer space; some numerical results of solutes in water will be shown and discussed. As further analyses, the introduction of Pauli repulsion term will be considered, and the implications all these effects have on molecular properties, such as (hyper)polarizabilities, numerically evaluated. The new approach has been implemented within the framework of the polarizable continuum model (PCM). (C) 1997 American Institute of Physics.