Free electron laser infrared action spectroscopy of nitrous oxide binding to platinum clusters, Pt(NO).

Infrared multiple-photon dissociation spectroscopy has been applied to study Pt(NO) (n = 1-8) clusters which represent entrance-channel complexes on the reactive potential energy surface for nitrous oxide decomposition on platinum. Comparison of spectra recorded in the spectral region 950 cm to 2400 cm with those simulated for energetically low-lying structures from density functional theory shows a clear preference for molecular binding via the terminal N atom, though evidence of O-binding is observed for some cluster sizes. Enhanced reactivity of Ptn≥ 6 clusters towards NO is reflected in the calculated reactive potential energy surfaces and, uniquely in the size range studied, Pt(NO) proved impossible to form in significant number density even with cryogenic cooling of the cluster source. Infrared-driven NO decomposition, resulting in the formation of cluster oxides, PtO, is observed following vibrational excitation of several Pt(NO) complexes.