Structural phase transitions in solids with applied stresses and fields, and effect of isotopic impurities on the free energy

Subject to the assumptions described in the text, an expression was obtained for the transition temperature T/subc/ associated with a structural phase transition. The change in energy, the pressure, stresses, and applied fields, the changes in volume, strains, and dipole moments, and determinant of the force constant matrix are considered. A result that may be useful for solids containing isotopic impurities is given