Adsorption of ethylene on Cu(410): A transfer-matrix and Monte Carlo study

Abstract Using the combination of Monte Carlo and transfer-matrix methods, we study the joint influence of the external (gas phase) pressure and temperature on the structure and thermodynamic properties of the ethylene adsorption layer on Cu(410) surface. It is found that the energies of interactions between the ethylene molecules adsorbed on the step-edge and terrace sites are different. Such interaction anisotropy and the actual heterogeneity of Cu(410) surface lead to the following sequence of the ordered phases in the adsorption overlayer with increase of the gas phase pressure. Phase 1/2S consisting of the alternating π-complexes and empty sites at the step-edge of the terraces (the surface coverage θ equals to 0.125) is formed continuously from the clean surface. Further increase of the pressure leads to the sequential appearance of the S ( θ  = 0.25) and S + T 2 ( θ  = 0.5) phases, wherein the step-edge and middle rows of the terrace are occupied by the ethylene π-complexes, respectively. We reveal that the adsorption on the middle row of the terrace can be described with 1D Langmuir model.