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Infrared spectra of NO adsorbed on an annealed polycrystalline Pt surface have been measured at temperatures between 300 and 673 K and under pressures of gas-phase NO between 10 −3 and 1 Torr. The spectra show that the NO adsorbate is in equilibrium with the gas phase at elevated temperatures. A model based on strong vibrational coupling between NO molecules adsorbed on adjacent Pt atoms is proposed to explain the observed spectra.

We have studied the infrared reflection-absorption spectrum of an adsorbate formed when an annealed polycrystalline Pt foil, presumably having a (111) surface structure, is exposed to ammonia gas at pressures in the range 0.1–10 torr. Isotopic substitution establishes that the adsorbate contains N2 in addition to NHx species. There is also CN present in the adsorbate, presumably formed by reaction of nitrogen with carbon impurities on the surface.