CONTINUUM AND DIPOLE-LATTICE MODELS OF SOLVATION

Citation
A. Papazyan et A. Warshel, CONTINUUM AND DIPOLE-LATTICE MODELS OF SOLVATION, JOURNAL OF PHYSICAL CHEMISTRY B, 101(51), 1997, pp. 11254-11264
Citations number
46
Journal title
JOURNAL OF PHYSICAL CHEMISTRY B
ISSN journal
15206106 → ACNP
Volume
101
Issue
51
Year of publication
1997
Pages
11254 - 11264
Database
ISI
SICI code
1089-5647(1997)101:51<11254:CADMOS>2.0.ZU;2-N
Abstract
Dipole-lattice and continuum-dielectric models, which are two importan t ''simplified'' models of solvation, are analyzed and compared. The c onceptual basis of each approach is briefly examined, and the relation ship between the two methodologies is explored. The importance of dipo le lattices in the development of dielectric theory is stressed. The C lausius-Mossotti equation, which is the result of early attempts at re lating the dielectric constant to ''microscopic'' quantities, also app lies to cubic lattices of Langevin dipoles or point polarizabilities. The presence of thermal fluctuations, rather than inter-dipolar or spe cific short range interactions is found to be the fundamental reason f or the deviation of dipolar materials from the Clausius-Mossotti equat ion. The fact that the continuum dielectric is the infinite dipole den sity limit of a more general dipole-lattice description is shown by re covering the continuum results with dipole lattices of high number den sity. The linearity of a continuum model is shown to be a direct conse quence of being the infinite density limit of a dipole lattice. Finall y, it is shown that the discreteness involved in the numerical solutio n of the Poisson equation cannot capture the effect of the physical di screteness in dipole lattices.