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Molecular-Based Virial Coefficients of CO2-H2O Mixtures



Allan H. Harvey, Andrew J. Schultz, David A. Kofke


We report values of the second and third virial coefficients for the system CO2-H2O, calculated as a function of temperature via numerical evaluation of cluster integrals that define the coefficients in terms of the intermolecular potential energy. Intermolecular interactions are described using quantitative models taken from the literature. One set of models is based on fits of highly accurate ab initio calculations of the potential energy surfaces, and another set is given as Gaussian Charge Polarization Models (GCPM) that were developed in part by fitting experimental data for the respective pure-component systems. Three-body effects are found to be essential for obtaining quantitative results. Good agreement with experimental data is obtained for the second and third virial coefficients of the pure components, and for the CO2-H2O cross second virial coefficient. For the two cross third virial coefficients between CO2 and H2O, the few experimental data available do not agree well with our calculations; it is not clear whether this is due to problems with the data or deficiencies in the three-body potentials used here. The uncertain state of the experimental data makes it likely that calculated mixture third virial coefficients could be more accurate than values from experiment, if sufficiently accurate three-body potentials are available.
Aiche Journal


carbon dioxide, thermodynamics, virial coefficients, water


Harvey, A. , Schultz, A. and Kofke, D. (2015), Molecular-Based Virial Coefficients of CO2-H2O Mixtures, Aiche Journal, [online], (Accessed April 24, 2024)
Created August 7, 2015, Updated November 10, 2018