The molecular adsorption of NO on both the reconstructed (hex) and unreconstructed (1 x 1) surfaces of Pt{100} was studied using a combination of infrared reflection-absorption spectroscopy and low-energy electron diffraction at temperatures between 90 and 300K. On the (1 x 1) surface at 300K adsorbed NO gives rise to an N-O stretching band at initially 1596/cm, shifting to 1641/cm at a coverage of θ = 0.5. The low-energy electron diffraction pattern at this coverage was interpreted in terms of a c(4 x 2) structure in which all the molecules occupy a single type of adsorption site between the on-top and bridge positions. At temperatures below 300K, a higher coverage disordered phase was observed, giving rise to an N-O stretching band at 1680/cm associated with an on-top NO species. On the (hex) phase surface above 210K, NO adsorption gives rise to bands characteristic of adsorption on the (1 x 1) phase indicating that the reconstruction was immediately lifted. Below 200K initial adsorption actually occurred directly on the (hex) phase, resulting in a band at 1680/cm, which was assigned to on-top NO. This band increased in intensity until, at a critical coverage dependent on temperature, the (hex) → (1 x 1) surface phase transition was induced. This was indicated by the disappearance of the band at 1680/cm and its replacement by bands characteristic of adsorption on islands of the (1 x 1) structure.

The Adsorbate-Induced Removal of the Pt{100} Surface Reconstruction I - NO. P.Gardner, M.Tüshaus, R.Martin, A.M.Bradshaw: Surface Science, 1990, 240[1-3], 112-24