The linear regression equation determining a dependence between crystal-nematic mesophase transition temperature, T-N, and energy of the torsion deformation, E(T), of the nematogene molecules has been obtained on the strength of calculations by the MM2 molecular mechanics method. It has been performed this transition occurs on reaching such value T-N which corresponds to the average quantity of the heat kinetic energy in respect to the two short molecule axes exceeding E(T). The methods of consideration of the intermolecular association have been examined.