Thermodynamics of Phase Transitions in Liquids in External Fields

We examine the conditions of phase equilibrium and transformations in a liquid located in an inhomogeneous external potential force field. If the force acting on the mass unit depends on the phase state, then a field-induced shift in phase equilibrium arises. As a result, at the phase interface at equal temperatures, the chemical potentials of the substance of phases do not coincide, although the full chemical potential is constant over the system. As well, one of the phases is located in a state which, in the absence of field, would be metastable. Such a field-induced phase equilibrium becomes impossible when one of the phases reaches the limiting state (spinodal). In this case, the system passes jumpwise into a new disperse state. We show that the above-mentioned features of phase equilibria in liquids and external fields manifest themselves in various physical systems and processes. These are electrical explosion of conductors, electrical explosion of micropoints on a cathode surface, and destruction of the surface of dielectrics by fast multicharged ions. Electric field also fosters the formation of nuclei of the competing phase in a supersaturated vapor and facilitates boiling of liquids on inhomogeneous heated surfaces. We discuss the possibility of achieving unusual states of substances, such as deeply supercooled hydrogen and ice at room temperature under the action of external fields.