Hard sphere
Figure 1.3: Schematic of the associating molecules as modeled in TPTl.
The potential of interaction between two associating fluid molecules 1 and 2, is
the sum of the spherically symmetric, hard core contribution, and the anisotropic,
association contribution.
uι2(r1,ωι,ω2) = u⅛(r) + J2 ∑ UABθc(r,ω1,ω2), (1.1)
A∈ΓW B∈Γ(2)
where ιtf2 ɪs the pair potential of the hard core reference fluid, u^^oc is the pair
potential due to association between site A on the molecule 1 and site B on molecule
2, is the set of all the associating sites on molecule i, r is the magnitude of the
vector r connecting the centers of the molecules 1 and 2, and α>1 and ω∙1 are the sets
of angles defining the orientations of molecules 1 and 2 relative to vector r. The pair
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