Application of the cell model to the statistical thermodynamics of r‐mers solutions. II

The cell model for r‐mers and r‐mer solutions developed by Prigogine, Trappeniers, and Mathot is applied to pure diphenyl, diphenylmethane, dibenzyl, and tolan (diphenylacetylene) and to their solutions in benzene. This model introduces new contributions for the excess functions arising from volume changes and modification of the curvature of intermolecular potential with change in composition. The excess functions are written in an explicit form and contain only molecular quantities without any arbitrary parameter. The agreement for the different excess functions (excess free energy, entropy, and excess volume) is satisfactory. The existence of a negative excess specific heat can also be understood on the basis of the cell model and is related to the negative excess volume.