Screening, dielectric

Klamt A and G Schuurmarm 1993. COSMO A New Approach to Dielectric Screening in Solvents witl Explicit Expressions for the Screening Energy and its Gradient. Journal of the Chemical Society, Perkii Transations 2 799-805. 

Klamt, A., Schtitirmann, G. COSMO a new approach to dielectric screening in solvents with explicit expressions for the screening energy and its gradient. 

A. Schiiurmann, G. COSMO a new approach to dielectric screening in solvents with explicit expressions for the screening energy and its gradient. J. Chem. Soc., Perkins Trans. 1993, 799-805. (c) Klamt, A. Jonas, V. Burger, T. Lohrenz, J. C. W. Refinement and parametrization of COSMO-RS. J. Phys. Chem. A 1998, 102, 5074—5085. (d) For a more comprehensive treatment of solvation models, see Cramer, C. J. Truhlar, D. G. Implicit solvation models equilibria, structure, spectra, and dynamics. Chem. Rev. 1999, 99, 2161— 2200. 

If the solute were simply a collection of point charges surrounded by a continuous dielectric medium with the bulk dielectric constant of the solvent, the self-energy and the strength of charge-charge interactions in the solute would be reduced by a factor of . This is called dielectric screening. However, the solute itself occupies a finite volume, and solvent is excluded from this volume. This reduces the dielectric screening and is called... 

Values of GENp calculated from the GB approximation compare well to values obtained from numerical solution of the Poisson equation for similar collections of point charges [83,237,238], A very promising extension of the GB methods is provided by a new scaled pairwise approximation to the dielectric screening integrals [215],... 

Some models carry the surface tension approach to extreme, and attempt to include even the electrostatic contributions in the surface tensions. These pure SASA models are obviously limited in their ability to account for such phenomenon as dielectric screening, but they have the virtue of being very easy to compute. Thus, they can be used to augment molecular mechanics calculations on very large molecules with a qualitative accounting for solvation. 

Sections III. 1-III. 3 have described some basic discrete molecular and continuum treatments of solute-solvent interactions. There are many variants and refinements of these that have not been discussed, such as the use of effective dielectric constants66 or the implementation of dielectric screening.155 156 For ionic solutions, it is sometimes preferred to find the reaction field potential via the Poisson-Boltzmann rather than the Poisson equation,132 157 since the effects of the other ions can readily be incorporated into the former.158... 

P(E) is called the irreducible polarization propagator, and W( ) the dielectrically screened interaction. 

On the other hand, electrostatic models regard the ligands or the whole crystal as polarizable units and thereby lead to weaker Coulomb and spin-orbit interactions. In a dielectric screening model (DSM) from Morrison et al. (1967) the f element is placed within an empty sphere with radius Rs which is embedded into an infinite medium with dielectric constant e. This leads to a reduction AFk of the Slater parameters (Newman, 1973) ... 

Experimental results for the Slater parameter reductions of Nd3+, Pr34-, and U3+ (Troster et al 1995) in LaCl under pressure up to 8 GPa in comparison with results from the dielectric screening model. All values in cm 1 3... 

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