The adsorption probability for NO/Pt(111) is highest for an initial orientation with the N end of the molecule towards the surface. This steric effect in the adsorption brings about a large averaged steric effect in the direct scattering, which is amplified by the fact that the adsorption probability is very high. In case of direct scattering an N-end collision results in a smaller reflection angle than an O-end collision.

• Received 1 March 1989

DOI:https://doi.org/10.1103/PhysRevLett.62.2152