The dynamics of a hard-core tracer particle which underwent biased random walks in an adsorbed monolayer, composed of mobile hard-core particles undergoing continuous exchanges with a vapor phase, were studied. An approximate approach was used which was based upon the decoupling of third-order correlation functions. The density profiles of monolayer particles around the tracer particle were obtained, and force-velocity relationships were derived which gave the tracer particle terminal velocity as a function of the magnitude of the external bias and of other system parameters. The results generalized, for the case of an arbitrary applied field, earlier predictions which had been obtained in the limit of a vanishingly small external bias. Asymptotic forms of the monolayer particle density profiles at large separations from the tracer particle, and the behavior of the terminal velocity in the limit of a small external bias, were found explicitly.

Force-Velocity Relation and Density Profiles for Biased Diffusion in an Adsorbed Monolayer. O.Bénichou, A.M.Cazabat, J.De Coninck, M.Moreau, G.Oshanin: Physical Review B, 2001, 63[23], 235413 (15pp)