The interaction of NO with 3 vicinal (111) surfaces having differing defect concentrations was studied by means of infra-red spectroscopy. The defect concentrations were deduced by using the adsorption of CO. This had well-characterized infra-red bands which were associated with bonding at defect sites. The adsorption of NO at these surfaces gave rise to numerous infra-red bands between 1320 and 1820/cm. Two of the NO bands corresponded to molecules at defect sites. Molecules which were bound at defect sites with a linear Pt-N-O configuration yielded an infra-red band in the range, 1820 to 1840/cm, while a bent Pt-N-O species at a defect site had a wave-number of 1609 to 1634/cm. This assignment of the bands was directly confirmed by blocking the defect sites with atomic O. Other infra-red bands were assigned to NO at terminal (1700 to 1720/cm) and 2-fold bridge sites (1475 to 1500/cm) of the (111) terraces.

V.K.Agrawal, M.Trenary: Surface Science, 1991, 259[1-2], 116-28