Eur. Phys. J. D 63, 231-234 (2011)
https://doi.org/10.1140/epjd/e2010-10480-8

Regular Article

CO adsorption on neutral iridium clusters

Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany

^a e-mail: fielicke@fhi-berlin.mpg.de

Received: 31 August 2010
Received in final form: 18 October 2010
Published online: 17 December 2010

Abstract

The adsorption of carbon monoxide on neutral iridium clusters in the size range of n = 3 to 21 atoms is investigated with infrared multiple photon dissociation spectroscopy. For each cluster size only a single ν(CO) band is present with frequencies in the range between 1962 cm^-1 (n = 8) and 1985 cm^-1 (n = 18) which can be attributed to an atop binding geometry. This behaviour is compared to the CO binding geometries on clusters of other group 9 and 10 transition metals as well as to that on extended surfaces. The preference of Ir for atop binding is rationalised by relativistic effects on the electronic structure of the later 5d metals.