Separation between fast and slow polarizations in continuum solvation models

Nonequilibrium solvation is important to describe many chemical processes in solution such as, for example, reactions involving light atoms or solvatochromic effects on UV spectra. This paper reports on an effective and general procedure to perform nonequilibrium calculations using continuum solvent models. First, "fast" dielectric constants are defined for the different processes which take place in solution (depending on their characteristic times), second, such constants are used in a new approach to separate fast and slow solvation components, and finally this approach is inserted in the framework of apparent surface charge (ASC) models. This procedure is applied to some test cases, involving very fast solute transitions which require the treatment of nonequilibrium effects.