We present a computer simulation study of orientational correlations in a molecular liquid approaching the isotropic-nematic transition, including the first calculation of the direct correlation function $c(1,2)$ in this regime. While the second-rank orientational correlation length diverges, the associated component of $c(1,2)$ remains short ranged, and its spatial integral approaches the mechanical instability limit for the isotropic phase as predicted by density-functional theory. Orientational correlation lengths and times are quite well described by Landau–de Gennes theory.

• Received 24 June 1996

DOI:https://doi.org/10.1103/PhysRevLett.78.1291