Density profiles of a dimerizing fluid in contact with a crystalline surface

The density profiles of an associating fluid near the (100) plane of the fcc crystalline surface are studied by using a singlet level theory of inhomogeneous associating fluids. The model for the bulk fluid is the one-component hard sphere fluid with an embedded sticky attractive site inside the hard core. This bulk fluid is treated using Wertheim's theory of associating fluids. The shape of the profiles is determined mainly by the overlap of the particles. At low densities, a depletion of the density profiles is observed. The stronger the adsorbing position, the stronger the depletion. Furthermore at low densities, the dimers, formed due to association in the bulk, tend to be adsorbed, with a nearly normal orientation, at the adsorption, or s, position of the unit lattice cell.