UNIQUAC interaction parameters have been successfully determined for three alkane/primary amine systems using a Molecular Mechanics method called the Consistent Force Field. Interaction parameters for alkane/alkane and alkane/ketone systems had been determined previously using this method and in this contribution the method has been extended to polar systems with extensive hydrogen bonding. It is thus possible to predict reliable vapor liquid equilibrium data using pure component data only. A method for finding the global minimum on the potential energy surface of a pair of molecules was developed. Good results were obtained in most cases but for a pair of cyclic molecules and a pair of ethylamine molecules this simple procedure was not satisfactory. A more objective method is desirable and the Boltzmann Jump search procedure seems to be such a method, Promising results have been obtained using the Boltzmann Jump search procedure for investigating the conformational space of a pair of molecules.