Are isotopic mixtures ideal?
G. Jancs�
KFKI Atomic Energy Research Institute, H-1525 Budapest
114, P.O.Box 49, Hungary
Abstract:
Isotopic mixtures have long been considered as textbook examples of
ideal solutions. High-precision vapor pressure measurements have shown
that even these very simple mixtures exhibit deviations from the ideal
behavior. The small, but still significant nonideality of isotopic mixtures
can be accounted for in terms of the difference in the molar volumes
of isotopic molecules. Theoretical analysis demonstrates that the internal
vibrations of the molecules significantly contribute to the excess Gibbs
energy, and the proper consideration of the volume dependence of molecular
vibrations of the component molecules is essential to the understanding
of the properties of isotopic mixtures.
*Lecture presented at the European Molecular Liquids
Group (EMLG) Annual Meeting on the Physical Chemistry of Liquids: Novel
Approaches to the Structure, Dynamics of Liquids: Experiments, Theories,
and Simulation,Rhodes, Greece, 7-15 September 2002. Other presentations
are published in this issue, pp. 1-261.
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