Cooperative Orientation in Solutions. The Accuracy of the Quasi-Chemical Approximation

Abstract

The accuracy of the quasi‐chemical approximation used in the theoretical treatment of a lattice model for solutions in which cooperative orientation of molecules takes place is examined. The quasi‐chemical method of Guggenheim and the modified quasi‐chemical method of Kikuchi are used to find higher approximations. It is found that the quasi‐chemical approximation for pairs is satisfactory for lattices which are not closepacked, though it may be seriously in error for closepacked lattices.