The structural second virial coefficient: II The intermolecular pair-potential for sulphur hexafluoride

J. G. Powles, J. C. Dore, Mohamad Deraman, E. K. Osae

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

The neutron scattering cross-section has been measured for low-density sulphur hexafluoride gas. The molecular term gives the S-F distance as 1-573 ±0-008 Å. The intermolecular term is analysed in terms of the structural second virial coefficient [1]. Although a Lennard-Jones (LJ) 12-6 potential fits the second virial coefficient over a wide range of temperature it is clearly inconsistent with our structural data at 20°C. Two intermolecular potentials have been found which fit both the second virial and the structural second virial coefficient data. One is a LJ 28-7 potential, virtually that proposed by Hamann and Lambert [14]. The other is a simple anisotropic site—site potential. The sites are at the fluorine nuclei and have LJ 12-6 potentials between sites with parameters, c/&b /T=61-39 and c/A = 3-024. The site-site potential is preferred on physical grounds. Neither a simple average nor a Boltzmann average of our site-site potential, which are virtually LJ 28-7 and LJ 12-6 respectively, has any apparent connection with the previously proposed LJ potentials. Moreover our proposed site-site potential differs substantially from a previous one [19] which was found suitable for the plastic crystal phase of SF6.

Original languageEnglish
Pages (from-to)1089-1108
Number of pages20
JournalMolecular Physics
Volume50
Issue number5
DOIs
Publication statusPublished - 1983
Externally publishedYes

Fingerprint

Sulfur Hexafluoride
Lennard-Jones potential
sulfur hexafluoride
Fluorine
Neutrons
virial coefficients
Neutron scattering
Plastics
Gases
Crystals
Temperature
T 61
scattering cross sections
fluorine
neutron scattering
plastics

ASJC Scopus subject areas

  • Biophysics
  • Molecular Biology
  • Physical and Theoretical Chemistry
  • Condensed Matter Physics

Cite this

The structural second virial coefficient : II The intermolecular pair-potential for sulphur hexafluoride. / Powles, J. G.; Dore, J. C.; Deraman, Mohamad; Osae, E. K.

In: Molecular Physics, Vol. 50, No. 5, 1983, p. 1089-1108.

Research output: Contribution to journalArticle

Powles, J. G. ; Dore, J. C. ; Deraman, Mohamad ; Osae, E. K. / The structural second virial coefficient : II The intermolecular pair-potential for sulphur hexafluoride. In: Molecular Physics. 1983 ; Vol. 50, No. 5. pp. 1089-1108.
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