Field-Aware Interfaces in Continuum Solvation

The continuum embedding approach has seen a rapid influx of interest from the condensed matter community in recent years. We present here a number of additions to the modelling of continuum interfaces that aim to provide an implicit consideration of charged species and compounds with highly polarized regions in an effort to further expand on the capabilities of continuum models, especially in the treatment of electrochemical interfaces. These advances follow recent approaches of using the electric field as an effective proxy for the localized charge surrounding a specific region. This “field-aware” approach is applied to the recently proposed soft-sphere continuum solvation (SSCS) method, wherein the radius of each soft-sphere composing the interface is readjusted as a function of the field flux through its surface, as well as the self-consistent continuum solvation (SCCS) method, whose interface definition is modified by the normal component of the electric field. In both cases, a complex dependence of the interface function on both the electronic and ionic degrees of freedom of the solute is introduced. Analytic derivatives of the new interface are thus implemented during optimization procedures (SCF and geometry optimization).