Experimental and theoretical studies of linear polyatomic molecules on surfaces of low symmetry: C2N2- on Pt(110)

The adsorption and surface dissociation of C₂N₂ on Pt(110), and the desorption kinetics of cyanide adlayers have been studied by LEED, Auger spectroscopy, and thermal desorption. The unusual adsorption kinetics which are accompanied by a (1 × 2) → (1 × 1) change in the surface periodicity are discussed in terms of absolute rate theory. The desorption process is modelled using 2D Monte Carlo and 1D analytical methods; these calculations indicate that the adlayer is only partly equilibrated — a conclusion which is confirmed by the results of CO coadsorption experiments. Values are deduced for the desorption parameters which suggest that the CN molecule is multiply bonded to the Pt surface.