Effective-charge concept in the pseudo-lattice approach for modeling the mean activity coefficient of electrolyte solutions

PHYS 315

Elsa Moggia, elsa@biosafetyengineering.it, (a) Department of Biophysical and Electronic Engineering, University of Genoa,Italy, (b) Biosafety Engineering TM, Italy, (a) Via Opera Pia 11 a, 16145 Genoa, Italy
The pseudo-lattice approach [E. Moggia, B. Bianco, J. Phys. Chem. B, 2007] provides a formula with one adjustable parameter to calculate the mean activity coefficients of electrolyte solutions for wide ranges of concentrations. The major advantage is that such a parameter is experimentally known for many systems. The basic idea is that of a lattice of ‘effective carriers of charge', each with a fixed amount of charge but whose spatial size increases with the concentration. Indeed one starts from a lattice of point-charge ions of the solute, at strong dilutions, and goes up to a lattice of local groupings of solute ions and solvent molecules at higher concentrations. The standard deviations from the mean positions (lattice-like)of carriers are also important and significantly affect the mean electrostatic energy per carrier. A comparison of the definition of effective carrier will be performed with other developments in literature involving effective-charge concepts.

PHYS Poster Session - Water Mediated Interactions
7:30 PM-10:00 PM, Wednesday, August 20, 2008 Pennsylvania Convention Center -- Hall C, Poster

Division of Physical Chemistry

The 236th ACS National Meeting, Philadelphia, PA, August 17-21, 2008