Adsorption-desorption processes of extended objects on a square lattice

Kinetics, of adsorption-desorption process is studied by Monte Carlo simulation on a square lattice. The depositing objects are squares covering nine lattice sites. At each Monte Carlo step adsorption is attempted with probability P-a and desorption with probability P-des = 1 - P-a. The equilibrium coverage and the relaxation time are obtained for various ratios of the adsorption probability to the desorption probability. The dependence of the relaxation time sigma on (P-a/P-des) is described by a power law sigma infinity (P-a/P-des)(2). The equilibrium coverage decreases exponentially with P-des/P-a for low desorption probabilities. (C) 2001 Elsevier Science B.V. All rights reserved.