Virial expression for the bulk pressure

By an approadi similar to the one outlined in Section E.3.1.1, we may derive a molecular expression for the bulk pressure Py, following again the original 

By the same logic applied before to Eq. (E.31), it is a simple matter to show that 

when summed over a and because of Eq. (E.64) these terms may be combined leading to 

Together Eqs. (E.70), (E.73), and (E.74) constitute tlie virial expression for the bulk pressure, which parallels Eq. (5.63) for the stress exerted by a con-fined fluid on the planar substrates of a slit-pore. 

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