Intermolecular forces in quasi-spherical molecules. Part 2

Abstract

The collision integrals necessary for the calculation of transport coefficients of gases have been computed for an intermolecular potential of the form 4(r) = A/+ -B/r7, where r is the distance between molecular centres. These integrals have been used in combination with existing second virial coefficient computations to test the suggestion that the 28 : 7potential describes the form of the intermolecular interactions which may be considered to occur between the centres of quasi-spherical molecules such as CF4, SF6, SiF4, or C(CH3)4.It is shown that such a potential approximation constitutes an improvement over the usual Lennard-Jones 12 : 6-potential for three of the quasi-spherical molecules, but it cannot be used to give a completely satisfactory correlation of the transport and equilibrium properties of these molecules.

Perturber dependence of the collision-induced light scattering by SF6and CF4

“…For SF6, two 28-7 Lennard-Jones potentials due to McCoubrey and Singh [14] and Powles et al [15] were available. Neumann [16] had developed a numerical potential to which we fitted an analytic expression of the HFD form: have developed modern potentials in the M3SV form [17,18].…”

“…The calculations have been performed with a 28-7 Lennard-Jones potential[14]. Downloaded by [McGill University Library] at 03:…”

Multiscale empirical mode decomposition of density fluctuation images very near above and below the critical point of SF6

“…One of the first studies done by Henry et al[42] examined viscosity data reported for other fluids near the critical point (xenon, CO, argon, krypton, nitrogen, oxygen, ethane, methane, and propane) and established a relation for the corresponding states. Combining results from[42] with the low-density SF 6 viscosity data[43,44] yields η(ρ c , T c ) ≈ 3.47 × 10 −5 P a • s[45,46]. Wu and Webb[46] found that for a reduced temperature range of1.22 × 10 −4 ≤ ≤ 6.90 × 10 −2 , there is no critical anomaly in share viscosity of SF 6 and η = (425 + 14.5(T c − T ) ± 15) × 10 −7 P a × s. A recent review of SF 6 data by Guder and Wagnera [47] used the following critical point values T c =(318.7232 ± 0.0020) K, p c =(3.754 983 ± 0.000 200) MPa, and…”

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

“…The calculated average of the square of the anisotropy can be approximately doubled by computing the thermal average using one of the modified LennardJones pair potentials for SF6 [23][24][25], thus substantially reducing the discrepancy between experimental and calculated values (see table 3 for a comparison of results with different potentials). Smaller but significant dependence of calculated depolarized light scattering intensities [26], depolarization ratios [11], and second Kerr virial coefficients [16] on the choice of pair potential has been reported previously.…”