Accurate effective potentials and virial coefficients in real fluids - Part IV. Heterodiatomic and polyatomic substances with permanent multipoles and their mixtures with noble gases
Je. Ramos et al., Accurate effective potentials and virial coefficients in real fluids - Part IV. Heterodiatomic and polyatomic substances with permanent multipoles and their mixtures with noble gases, PHYS CHEM P, 3(13), 2001, pp. 2634-2643
The approximate nonconformal (ANC) theory recently proposed has been very s
uccessful for determining effective interaction parameters from the measure
d gas imperfection B(T) for a variety of substances, from the noble gases t
o perfluoro-n-alkanes. Here we report the application of the ANC treatment
to the polar substances: NO, CO, HCl, CO2, H2O, D2O, NH3, CH2:CH2 and SF6 a
nd predict the cross interactions in the mixtures of these substances with
noble gases. The theory is successful in describing B(T). It also permits u
s to extract atom-atom potential parameters for CO. The resulting C-C inter
action follows the simple dependence on atomic number already found for oth
er atoms. For NO, which is partially dimerised in the gas phase, and using
the approach pioneered by Guggenheim and Scott, the ANC theory gives a very
good account of the observed B(T) for partially dimerised NO. Lastly, the
ANC prediction of the cross virial coefficient is in excellent agreement wi
th experiment in all but one of the binary mixtures considered.