Atom diffusion in a simple cubic lattice:: Real-space renormalization group and Monte Carlo calculations

A three-dimensional simple cubic lattice gas is investigated by using the real-space renormalization group (RSRG) approach with blocks of different size and symmetries. We have calculated absorption isotherms and density dependencies of the pair correlation function, isothermal susceptibility, chemical and jump diffusion coefficients for different temperatures. All these quantities have also been obtained by Monte Carlo (MC) simulations. We have also obtained the density dependencies for the tracer diffusion coefficient by MC simulations. Despite the fact that both methods constitute very different approaches, the correspondence of numerical data and theoretical results is rather good. We conclude that the RSRG method can be applied to the three-dimensional lattice gas system discussed here to characterize its thermodynamic and kinetic properties.