Lattice calculations for concentrated solutions

These results are highly signihcant and mark a considerable improvement on the Debye- 

These are models which attempt to take into consideration the molecular structure of the solvent molecules. Previous treatments based on the Debye-Hiickel model have approximated the solvent to a continuous medium characterised simply by the macroscopic relative permittivity. Qualitatively, the Bom-Oppenheimer models could be taken as replacing the Gurney terms and the cavity terms of the previous model (Sections 10.16.3 to 10.16.6). 

The model requires potential energies describing interactions between  

These potential energies can be made as simple or as complex as desired. 

Analysis of this model of the electrolyte solution takes the above quantities and by carrying out statistical mechanical calculations or Monte Carlo calculations leads eventually to a calculation of activity coefficients for a range of ionic strengths. The details of the procedures are complex. Results can be compared with experiment, or with the results of other theoretical treatments and indicate that this is a very fiuitfid line of enquiry. The extension to allow for the molecular nature of the solvent is a very necessary step in leading to an eventual fuU description of the behaviour of electrolyte solutions. 

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