Force-velocity relation and density profiles for biased diffusion in an adsorbed monolayer -: art. no. 235413

We study the dynamics of a hard-core tracer particle (TP), performing a biased random walk in an adsorbed monolayer composed of mobile hard-core particles undergoing continuous exchanges with a vapor phase. In terms of an approximate approach, based on the decoupling of the third-order correlation functions, we obtain the density profiles of the monolayer particles around the TP, and derive the force-velocity relation, determining the TP terminal velocity V-tr as a function of the magnitude of the external bias and other system parameters. These results generalize, for the case of an arbitrary applied field, our earlier predictions [Phys. Rev. Lett. 84, 511 (2000)] obtained in the limit of a vanishingly small external bias. Asymptotic forms of the monolayer particle density profiles at large separations from the TP, and the behavior of V-tr in the limit of a small external bias, are found explicitly.