Statistical mechanical model with chemical reaction

We study a mixture of classical particles where unequal particles interact with strong binding forces, while equal particles repel each other with a hard-core interaction. The interactions are constructed so that at most two unequal particles can bind to a molecule. Such a system can be interpreted as one where the basic species react to form diatomic molecules, the equilibrium of which at low densities is governed by the well-known law of mass action. Our results explicate and supplement the approach of Andersen to this problem.