Professor Van Hook is supported by a grant from the Theoretical and Computational Chemistry Program to measure thermodynamic isotope effects in vapor and liquid phases. Virial coefficients, vapor pressures, condensed phase partial molar volumes, compressibilities and expansivities, and the isotope effects on these properties will be measured between room temperature and the critical temperature, and from less than 0.1 to 200 MPa. In a second and complementary project, refractive index differences between isotopic isomers, and between liquids and solutions will be measured. The theoretical analysis of the results will focus on the relation between intermolecular forces in the condensed phase and the molecular properties, especially the polarizability, and will include consideration of the contributions from isotope effects from different normal mode vibrations. %%% Systematic and accurate measurement of thermodynamic properties is extremely important for the development of theories of intermolecular interactions in vapors, liquids, and solutions as well as for more practical reasons. The current research program will produce precise data for small differences in thermodynamic properties which result from isotopic substitution. This research will also provide some of the most accurate thermodynamic data available on the reference compounds used. The data produced will provide a valuable resource to the larger community of chemists and chemical engineers.
