modified Benedict–Webb–Rubin — Lennard-Jones flexible tangent chain
This noncubic EOS describes the behaviour of the Lennard-Jones fluid as well as flexible LJ tangent-sphere chains.
The EOS consists of a BWR EOS for single LJ spheres and an extension term for chain molecules [1, 2]. It is based on a more extensive and more accurate set of computer simulations than its predecessor, the Nicolas EOS [3]. The chain term is based on the behaviour of the background correlation function (cavity correlation function) at contact and uses a superposition approach to relate this function for chain molecules to that of spherical particles.
Users interested in the accurate representation of the LJ EOS should also consider the EOSs of Kolafa and Nezbeda, Quiñones-Cisneros, Mecke et al., May and Mausbach, or Thol et al.. For 2-center LJ molecules, the EOS of Lísal et al. can be recommended.
The critical compression factor of this EOSs is somewhat too high (0.319 for 1-center LJ molecules) and increases with chain length, in contrast to the behaviour of real molecules.
adjustable parameters: 3
The ThermoC parameters are
T* = ε/kB,
v* = NAσ3,
and m (number of sites).
[1] J. K. Johnson, J. A. Zollweg, K. E. Gubbins, Mol. Phys. 78 (1993) 591–618.
[2] J. K. Johnson, E. A. Müller, K. E. Gubbins, J. Phys. Chem. 98 (1994) 6413–6419.
[2] J. J. Nicolas, K. E. Gubbins, W. B. Streett, and D. J. Tildesley, Mol. Phys. 37 (1979) 1429–1454.
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