Vapor Pressure Isotope Effects

The vapor pressure isotope effect is a reflection of the thermodynamic relations in the condensed phase. It is possible to explain the observed effects on the basis of intermolecular vibrations, e.g. hydrogen bond vibrations, and the frequency shifts of the charateristic vibrations on condensation, though other effects must also be discussed. Information about the thermodynamics of liquids, e.g. about the degree of association or the expected positions of the lattice frequencies, can be obtained from the vapor pressure isotope effect.