Intermolecular Forces in Globular Molecules. IV. Additive Third Virial Coefficients and Quadrupolar Corrections

Additive third virial coefficients for a spherical‐shell potential have been computed for varying shell sizes corresponding to r0*=1.4, 1.6, 1.8, 2.0, 2.5, 3.0, and 4.0, and a temperature range 0.4<T*<10.0. In addition, the first quadrupolar correction has been computed for this model. The resulting expressions are compared with experiment for seven globular molecules employing force constants deduced independently from second virial data alone. For the simpler substances the spherical‐shell and Lennard‐Jones (12–6) models are about equally useful in representing the data. For the truly globular molecules, however, the spherical‐shell potential is a marked improvement, although Cadd alone is insufficient to represent the data. Corrections for nonadditive forces are discussed briefly and qualitatively. An argument is made to show that such corrections to spherical‐shell results for globular molecules can be expected to improve the fit, whereas similar corrections to Lennard‐Jones (12–6) may not. For the ca...

[1]  R. Kobayashi,et al.  Negative Third Virial Coefficients , 1966 .

[2]  D. A. Mcquarrie,et al.  Second and Third Ordinary and Dielectric Virial Coefficients for Nonpolar Axial Molecules , 1966 .

[3]  E. A. Mason,et al.  Nonadditivity of Intermolecular Forces: Effects on the Third Virial Coefficient , 1966 .

[4]  A. Rocco,et al.  Intermolecular Forces: The Triangle Well and Some Comparisons with the Square Well and Lennard‐Jones , 1964 .

[5]  J. Prausnitz,et al.  Third Virial Coefficient for the Kihara, Exp‐6, and Square‐Well Potentials , 1964 .

[6]  D. R. Douslin,et al.  The Pressure-Volume-Temperature Properties of Perfluorocyclobutane Equations of State, Vital Coefficients, and Intermolecular Potential Energy Functions , 1959 .

[7]  E. A. Mason,et al.  Compressibility and Intermolecular Forces in Gases: Methane , 1958 .

[8]  W. Schneider,et al.  THE COMPRESSIBILITY OF GASES AT HIGH TEMPERATURES: X. XENON IN THE TEMPERATURE RANGE 0° TO 700 °C. AND THE PRESSURE RANGE 8 TO 50 ATMOSPHERES , 1955 .

[9]  J. Beattie,et al.  The Compressibility of Gaseous Krypton. II. The Virial Coefficients and Potential Parameters of Krypton , 1951 .

[10]  W. Schneider,et al.  Compressibility of Gases at Pressures up to 50 Atmospheres. V. Carbon Tetrafluoride in the Temperature Range 0°—400°C. VI. Sulfur Hexafluoride in the Temperature Range 0°—250°C , 1951 .

[11]  A. Rocco,et al.  Intermolecular forces in globular molecules III: a comparison of the spherical shell and Kihara models , 1967 .

[12]  H. Frisch,et al.  Conditions Imposed by Gross Properties on the Intermolecular Potential , 1960 .

[13]  J. S. Rowlinson,et al.  The physical properties of some fluorine compounds and their solutions. Part 1.—Sulphur hexafluoride , 1955 .

[14]  T. Wassenaar,et al.  Isotherms of xenon at temperatures between 0°C and 150°C and at densities up to 515 Amagats (pressures up to 2800 atmospheres) , 1954 .

[15]  A. Michels,et al.  Isotherms of methane between 0° AND 150°C and densities 19 and 53 amagat (Pressures between 20 and 80 ATM.) , 1935 .