Effects of correlations and lattice gas restriction on the collective diffusion

J.R. SÁNCHEZ Y C.M. ALDAO

SURFACE SCIENCE

Año: 2001 vol. 479 p. 224 - 230

0039-6028

The combined effects of correlations and lattice gas restriction on the collective diffusion behavior of one-dimensional concentration profiles are studied.  Correlations are introduced as a persistent or anti-persistent movement in the individual random walk performed by the diffusing particles.  The value of the diffusivity as a function of correlation is obtained for the continuous case through a new and simple analytical method.  For the single occupancy (lattice gas) case, the collective diffusion coefficient is calculated by using the Boltzmann-Matano method.  It is shown that the collective behavior of the system makes the concentration profiles not to scale, and the values of the diffusion coefficient become dependent on the type and amount of correlation and on the local concentration when the single occupancy restriction is present.