Aah. Padua et Jpm. Trusler, APPLICATION OF INTEGRAL-EQUATION THEORIES TO THE NITROGEN MOLECULE, The Journal of chemical physics, 105(14), 1996, pp. 5956-5967
The Percus-Yevick (PY) and the hypernetted chain (HNC) integral equati
ons have been applied to realistic, non-spherical, intermolecular pote
ntials for nitrogen. Non-additive contributions, in the form of the Ax
ilrod-Teller three-body interaction, have been considered. The integra
l equations were solved after expansion in spherical harmonics and the
solution procedure is described in detail. Thermodynamic properties o
f the gas calculated through the compressibility and the virial routes
are in surprisingly good agreement with experimental data. Typical de
viations are within +/-0.2 per cent for both p rho T and sound-speed d
ata at sub-critical densities. Some improvement may be achieved by fit
ting the three-body dispersion coefficient. We conclude that a simple
integral-equation theory and a reasonably sophisticated anisotropic pa
ir potential, coupled with the Axilrod-Teller three-body term, can off
er a good description of the thermodynamic surface at sub-critical den
sities. A closure more accurate than either PY or HNC will be required
if good results are to be obtained at densities above the critical. (
C) 1996 American Institute of Physics.