Adsorbed n-hexadecane films of thickness ∼10, 20, and 40 Å are studied at 350 K via molecular-dynamics simulations. In the thickest film periodic oscillations of the density extend ∼18 Å from the solid-liquid interface, the roughness fluctuations at the liquid-vapor interface are Gaussian, and the density tail is fitted by an error function. Molecules in the first adsorbed layer lie preferentially parallel to the surface exhibiting domains of intermolecular orientational alignment. The diffusion is anisotropic with the component parallel to the surface greatly enhanced in the liquid-vapor region.

• Received 3 February 1992

DOI:https://doi.org/10.1103/PhysRevLett.69.1967