An approximate theory for tracer diffusion in a lattice which contained randomly distributed traps, and in the presence of a finite concentration of diffusing particles which prevented the double occupancy of any site, was developed. This was done by extending earlier theories of diffusion, in many-particle systems in perfect lattices, by using random-walk concepts. Both blocking and dynamic correlation effects were considered. The theoretical results were compared with computer simulations, of a 2-dimensional square lattice with 2 types of trap, over the entire concentration ranges of particles and traps. The agreement between the simulation results and theory was satisfactory, and suggested that the approximation would be valid for models of diffusion in disordered lattices.

Tracer Diffusion in a System with Randomly Distributed Traps L.F.Perondi, R.J.Elliott, K.Kaski: Journal of Physics - Condensed Matter, 1997, 9[38], 7949-61