We present the results of molecular-dynamics simulations of systems of dumbbell molecules confined by parallel molecular walls. We have carried out systematic studies of three cases: freezing, steady flows, and stick-slip friction. We find that the molecular orientational degrees of freedom cause the surface layers to deviate from a planar configuration. Nevertheless, steady flows, in a channel as narrow as 15 molecular sizes, display continuum behavior. A range of mechanisms in the dynamics of the freezing of a confined fluid is found, as a function of the wall-fluid interactions and the bond length of the dumbbell molecules. The simple order-disorder transition associated with stick-slip motion in the presence of a layer of monoatomic lubricant molecules is supplanted by more complex behavior due to rotational degrees of freedom of the diatomic molecules.
Ma, W.J., Iyer, L.K., Vishveshwara, S., Koplik, J., Banavar, J.R., Molecular-Dynamics Studies of Systems of Confined Dumbbell Molecules, Physical Review E, The American Physical Society, College Park, MD, Vol. 51 (1), pp. 441-453, January, 1995.