Experimental results, obtained using a molecular beam reflectivity method, for the probability of molecular physical adsorption of ethane on the Ir(110)-(1x2) surface were presented. These results were analyzed using Monte Carlo simulations and showed that molecular adsorption could occur either "directly" or through a precursor state in which an ethane molecule was trapped in a second layer of molecularly adsorbed ethane with subsequent migration to a vacant site. From the Monte Carlo simulations, it was possible to establish that the energy barrier for the desorption of an ethane molecule from the precursor state was approximately 4.5kcal/mol. It was also that the energy barrier for diffusion of an ethane molecule on top of a monolayer of ethane molecularly adsorbed on the Ir(110)-(1x2) surface was approximately 3.7kcal/mol.

Molecular Adsorption of Ethane on the Ir(110)-(1x2) Surface: Monte Carlo Simulations and Molecular Beam Reflectivity Measurements. H.C.Kang, C.B.Mullins, W.H.Weinberg: The Journal of Chemical Physics, 1990, 92[2], 1397-406