Interaction Polarizabilities

Contributing to Ajj are, in addition to the solvent structural effects explicitly considered, contributions from dielectric saturation, from the liquid structure effects one has even in simple fluids, from solvent-mediated dispersion interactions of the ions, from charge-polarizability interactions of the ions, and so on. It is difficult to tell a-priori which effects are dominant or how big they are. However the collection of A 5 coefficients has characteristics that are consistent with the first named effect being dominant. 

This term is a measure of the exoergic balance (i.e. release of energy) of solute-solvent and solute-solute dipolarity / polarizability interactions. This term, denoted by n, describes the ability of the compound to stabilize a neighbouring charge or dipole by virtue of nonspecific dielectric interactions and is in general given by -> electric polarization descriptors such as -> dipole moment or other empirical - polarity / polarizability descriptors [Abraham et al, 1988]. Other specific polarity parameters empirically derived for linear solvation energy relationships are reported below. 

Fig. 1. Qualitative representation of the effect of electrostatic, hydrogen-bonding, and mutual polarizability interactions on the free energy of solvation of anions in methanol and in DMF. (cf. Table 26).

The good agreement obtained between the measured and calculated d.m. (taking into account the N-methyl group d.m.) is evidence of a slight reciprocal polarizable interaction between the imidazole and pyridine rings. This confirms the adequacy of the chosen method used for the calculation of the resultant d.m. for IbP. 

Ohtori, N., Salanne, M., and Madden, P.A. (2009) Calculations of the thermal eonductivities of ionic materials by simulation with polarizable interaction potentials, J. Chem. Phys. 130,104507 (2009). 

Hemandez-Cobos J, Ramirez-Solis A, Maron L, Ortega-Blake I (2012) Theoretical study of the aqueous solvation of HgC12 Monte Carlo simulations using second-order Moller-Plesset-derived flexible polarizable interaction potentials. J. Chem. Phys. 136 014502... 

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