Virial coefficients of hard convex molecules in two dimensions

Abstract

Third, fourth and fifth virial coefficients are reported for isotropic 2-dimensional fluids of hard convex molecules of elliptical and spherocylindrical shapes, covering a wide range of elongations. Similar results are also included for hard lines of unit length, to give values in the limit of extreme elongation. Comparison with recent results for B ₃ and B ₄ confirms their values. Both B ₄ and B ₅ become negative when the elongation is large. For B ₄ this occurs only at very extreme elongations, around 50:1 for ellipses, and an even larger value for spherocylinders, while B ₅ becomes negative at much lower elongations, around 6:1 for ellipses.