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First-Principles Calculation of the Air-Water Second Virial Coefficient



Allan H. Harvey, Peter H. Huang


Recent theoretical work has produced quantitatively accurate potential-energy surfaces for water with common gases. These pair potentials have been used to calculate cross second virial coefficients with an accuracy superior to that obtained by most experiments. In this work, we combine results for water-nitrogen, water-oxygen, and water-argon to calculate an effective second virial coefficient for water with air. Our results are in agreement with the existing experimental data, but they cover a wide range of temperatures while the experimental data only extend from 253 K to 348 K. These results will be useful for humidity standards and other applications requiring thermodynamic properties of moist air.
International Journal of Thermophysics


air, enhancement factor, humidity, second virial coefficient, water


Harvey, A. and Huang, P. (2007), First-Principles Calculation of the Air-Water Second Virial Coefficient, International Journal of Thermophysics, [online], (Accessed April 18, 2024)
Created April 1, 2007, Updated October 12, 2021