Reaction field treatment of charge penetration

Treatment of the important electrostatic effects of solvation by means of r eaction field theory is becoming common in electronic structure calculation s on molecules. Most extant reaction field methods neglect or crudely appro ximate the often important influence of volume polarization arising from so lute charge that quantum mechanically penetrates outside the cavity that no minally encloses it. This work proposes and examines a new formulation that provides an accurate simulation of volume polarization effects while being much simpler to implement and use than an exact treatment. Detailed compar isons with other related methods are also given. (C) 2000 American Institut e of Physics. [S0021-9606(00)30513-X].