Infrared action spectroscopy of nitrous oxide on cationic gold and cobalt clusters

Abstract

Understanding the catalytic decomposition of nitrous oxide on finely divided transition metals is an important environmental issue. In this study, we present the results of a combined infrared action spectroscopy and quantum chemical investigation of molecular N₂O binding to isolated Au_n⁺ (n ≤ 7) and Co_n⁺ (n ≤ 5) clusters. Infrared multiple-photon dissociation spectra have been recorded in the regions of both the NO (1000–1400 cm⁻¹) and NN (2100–2450 cm⁻¹) stretching modes of nitrous oxide. In the case of Au_n⁺ clusters only the ground electronic state plays a role, while the involvement of energetically low-lying excited states in binding to the Co_n⁺ clusters cannot be ruled out. There is a clear preference for N-binding to clusters of both metals but some O-bound isomers are observed in the case of smaller Co_n(N₂O)⁺ clusters.