The Theory of Phase Transitions

Abstract

THE only phase transitions which up to the present time have been thoroughly investigated are transitions between the liquid and gaseous states. As regards transitions between liquids and crystals or between different crystalline modifications, their treatment has not always been quite satisfactory. For example, one sometimes hears not only of transition points (with jumps of energy) and Curie points (with jumps of specific heat), but also of transition points of the nth order, as if there were reason to assume that such generalized transitions can really exist. Some transitions have been attributed to the rotation of molecules, although I cannot see how rotation by itself can lead to discrete transitions. The idea seems to exist that there can be an absolutely continuous transition between the liquid and crystalline state (analogous to the transition liquid-gas), which would require the existence of a miraculous state which is neither isotropic nor anisotropic.