Random walks on a fluctuating lattice: A renormalization group approach applied in one dimension

Diffusion of particles over dynamically disordered lattice

Using kinetic Monte Carlo simulations we have investigated the diffusion of particles over a lattice with moving atoms in the framework of a simple lattice-gas model of a reconstructive surface. The particle migration over the static and dynamic lattices differs considerably. The dynamic lattice reconstruction changes substantially the particle diffusion coefficient. The Arrhenius dependencies are quantitatively different. An interesting peculiarity of the particle migration is the formation of defectons--local lattice deformations around the adsorbed particles. In certain ranges of the system parameters (jump rates of the substrate atoms and adsorbed particles) the adsorbed particles cause local displacements of the nearest substrate atoms, resulting in deeper adsorption sites and lower jump rates. Such particle self-trapping produces a characteristic minimum on the Arrhenius dependencies.

Transport in two-dimensional scattering stochastic media: simulations and models

Classical transport of neutral particles in a purely scattering two-dimensional stochastic media is studied. Results of numerical Monte Carlo simulations of transport in two-dimensional stationary, binary, purely scattering stochastic media with Markovian mixing statistics are reported. Partial Markovian descriptions are proposed as models for the transport process inside the stochastic media. In these models, the composition of the media is correlated on a finite length scale. The results obtained from the models are in good agreement with the results obtained from the two-dimensional simulations.