High-precision heat-capacity and molecular-dynamics-simulation studies on the orientational transition of nitrogen molecules adsorbed on graphite are reported here. The peak in the heat-capacity data is rather narrow and shows no observable finite-size effects. The simulation studies show that, in addition to the loss of orientational order in the plane of the surface, significant reorientation in the direction perpendicular to the surface is also found as temperature is increased.

• Received 24 January 1983

DOI:https://doi.org/10.1103/PhysRevLett.51.192