Variations of the rotational energy distributions of NO molecules scattered at a Pt(111) surface have been determined by means of laser-induced fluorescence. Scattering of a rotationally cold (32 K) supersonic molecular beam at a NO-covered surface results in full rotational accommodation due to trapping/desorption. No Boltzmann distribution of the rotational energies is observed if the molecules are directly (specularly) scattered at a graphitic overlayer.

• Received 5 November 1980

DOI:https://doi.org/10.1103/PhysRevLett.46.152