Results for attractive interaction

Diffusion coefficients obtained in this way are shown in Fig. 48 for the results of diffusion in two dimensions with and without lateral interactions. D is much reduced at high coverages for attractive interactions and is increased for repulsive interactions. Dilute layers tend to the value of D for no lateral interactions. In the random walk situation for the fourfold symmetric surface, D is related to T by [409] 

See the solution to Exercise 2.30(a) and Example 3.6, where it is demonstrated that jrj- = a/V for a van der Waals gas. Therefore, there is no dependence on b for a van der Waals gas. The internal pressure results from attractive interactions alone. For van der Waals gases and liquids with strong attractive forces (large a) at small volumes, the internal pressure can be very large. 

Recently, the HAB approach plus the MV closure has been applied both to hard spheres near a single hard wall [24,25] and in a slit formed by two hard walls. Some results [99] for the latter system are compared with simulation results in Fig. 7. The results obtained from the HAB equation with the HNC and PY closures are not very satisfactory. However, if the MV closure is used, the results are quite good. There have been a few apphcations of the HAB equation to inhomogeneous fluids with attractive interactions. The results have not been very good. The fault hes with the closure used and not Eq. (78). A better closure is needed. Perhaps the DHH closure [27,28] would yield good results, but it has never been tried. 

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