Energy disposal in collisions of nitric oxide with molecular adlayers on transition metal single crystal surfaces: Rotational energy disposal

The dynamics of the scattering of nitric oxide (NO) from well-characterized and ordered layers of carbon monoxide (CO) and ethylidyne (CCH3) adsorbed on a Pt(111) substrate have been investigated through resonance-enhanced mu ltiphoton ionization (REMPI) measurements of the rotational quantum state d istributions of the scattered NO molecules for a range of incident NO trans lational energies between 10 and 50 kJ mol(-1) from scattering substrates a t 108 and 300 K. The measurements reveal that, where in principle the inter action potential resembles that of the NO-Ag(111) system more so than that of the NO-Pt(111) system, the scattering differs remarkably from that expec ted from a weakly bound system in that it occurs both into a trapping-desor ption channel and a direct inelastic channel. Experimental data are present ed that indicate both an incident translational energy dependence and subst rate surface temperature dependence of the scattering, which is interpreted in terms of a hard-cube model. (C) 2000 American Institute of Physics. [S0 021-9606(00)70343-6].