Intermolecular Potentials. I. Carbon Tetrafluoride and Sulfur Hexafluoride. II. Carbon Dioxide

Abstract

Experimental second virial coefficient data for carbon tetrafluoride, sulfur hexafluoride, and carbon dioxide have been used to investigate the intermolecular potentials of these molecules on the basis of a Lennard-Jones model. Force constants for the fluoride molecules can be fitted rather satisfactorily, but the constants so derived do not agree with those derived from other gaseous properties, e.g., the critical data. This result may be due to the assumption of central forces for the symmetrical fluoride molecules. For carbon dioxide it was found that the derived force constants varied with temperature, the high temperature data yielding lower values of the collision diameter r0. The results can be interpreted on the basis of a partial association. A likely configuration for the resulting dimer is suggested.

Inert fluorinated gas T1 calculator

“…Our model works well with JohnsonÕs data, and the common parameters agree. As a second comparison, we tried fitting our SF 6 data with the virial equation of state [31] that [13] used instead of the Clausius equation. The results ( Table 2) are the same.…”

The three body correlation spectrum in collision induced light scattering by isotropic molecular gases

“…12-6 potential : ~/k=259 K, o=5.01A [22]. 12-6 potential : c/k=200.9 K, o=5.51]k [20]. 28-7 potential : ~/k=439 K, o=4.68 A [21].…”

The pair polarizability anisotropy of SF6in the point-atom-polarizability approximation

“…Results for T= 300 K are given relative to the results obtained by Buckingham and Dunmur [4] using a Lennard-Jones potential [14]. (a) Reference [14]. polarizability anisotropy.…”

“…Thermal averages of the squared pair polarizability anisotropy in the dipoleinduced-dipole approximation, ,(x-~ )DIDO), computed with different pair potentials for SF6. Results for T= 300 K are given relative to the results obtained by Buckingham and Dunmur [4] using a Lennard-Jones potential [14]. (a) Reference [14].…”

“…(4) Although values accurate to within 30 per cent for the pair polarizability anisotropics of inert gas atoms can be obtained from the DID model [4,[6][7][8][9][10], the model is not generally adequate for molecules with structure. For SF6, the experimental values for the depolarized light scattering intensity [7,11,12] and the second Kerr virial coefficient [4,13] are two to three times the values obtained by calculating the thermally averaged square of the polarizability anisotropy with -the DID model and a Lennard-Jones pair potential [14].…”