An exactly solvable model threehyphen;component solution with a double critical point

摘要

A lattice model of a threehyphen;component solution is considered in which the bonds of a lattice are covered by molecules of types AA, BB, and AB. Unlike molecular ends near a common site have orientationhyphen;dependent interactions. For small but constant AB concentrations, the system exhibits a closedhyphen;loop phase diagram. The closed loop shrinks as the concentration of AB molecules increases and vanishes at a double critical point. Exact results are presented for the model on a threehyphen;coordinate Bethe lattice.