MULTILAYER ADSORPTION OF BINARY-MIXTURES - MEAN-FIELD THEORY AND MONTE-CARLO SIMULATION

The formation of two-component multilayer films on homogeneous solid s urfaces is discussed using the mean-field theory and Monte Carlo simul ation. Adsorption systems exhibiting complete and incomplete mixing of components are discussed. It is shown that the structure of adsorbed films depends strongly on the relative strength of the adsorbate-adsor bate and the adsorbate-substrate interactions for both components. In particular, it is demonstrated that the enhanced adsorption of one com ponent due to adsorption of another gas, which is observed in monolaye r films, occurs also in multilayer films. It is shown that in the syst ems considered in this work the displacement of preadsorbed film due t o adsorption of the second component may occur via the desorption or v ia the transfer of molecules to the higher layers. The mechanism of th e displacement is shown to depend strongly on the details of gas-gas a nd gas-solid interactions of both components.