Random sequential adsorption and diffusion of dimers and k-mers on a square lattice

We have performed extensive simulations of random sequential adsorption and diffusion of k-mers, up to k = 5 in two dimensions with particular attenti on to the case k = 2. We focus on the behavior of the coverage and of vacan cy dynamics as a function of time. We observe that for k = 2,3 a complete c overage of the lattice is never reached, because of the existence of frozen configurations that prevent isolated vacancies in the lattice to join. Fro m this result we argue that complete coverage is never attained for any val ue of k. The long time behavior of the coverage is not mean field and nonan alytic, with t(-1/2) as leading term. Long time coverage regimes are indepe ndent of the initial conditions while strongly depend on the diffusion prob ability and deposition rate and, in particular, different values of these p arameters lead to different final values of the coverage. The geometrical c omplexity of these systems is also highlighted through an investigation of the vacancy population dynamics. (C) 2001 American Institute of Physics.