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Cavity boundary effects within the onsager theory for dielectrics
Author(s) -
Ehrenson S.
Publication year - 1981
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.540020109
Subject(s) - dielectric , dipole , permittivity , intramolecular force , intermolecular force , boundary value problem , laplace transform , lattice (music) , range (aeronautics) , statistical physics , materials science , chemistry , thermodynamics , physics , molecule , quantum mechanics , mathematics , mathematical analysis , acoustics , composite material
Means by which the Onsager theory of dielectrics may be modified in a general way to include important structurally nonspecific electrical effects exercised at or near the cavity boundary are developed and discussed. In essence they rely upon extraction of limiting numerical solutions of the Laplace equation potentials for multiple shells approximating regions of smoothly varying permittivity surrounding the dipole‐containing cavity. The results of several such modifications, which usefully retain the original reaction and cavity field forms, are applied to evaluate the dielectric constants of polar solvents acting as support media for mean‐space‐charge attenuation of intracavity electrical interactions, and in correlation of isolated molecule and condensed phase properties of formally nonassociated solvents. For the most part such predictions and correlations are found to be improved by a wide variety of physically reasonable continuity functions. Where they are not, more rational patterns of deviations consistent with possible modes of intramolecular charge transfer and weak intermolecular association in formally nonassociated liquids are detected. Some limited comparisons with particle‐ and structure‐dependent theories, e.g., the mean spherical model and discrete lattice formulations, also suggest that the present permittivity modifications can effectively simulate important short‐range nonspecific liquid ordering effects. Various factors relating to possible adaption of the limit procedures developed to other inhomogeneous dielectric medium calculations are also briefly outlined.