The structures of small cationic gas-phase platinum clusters

The structures of small platinum clusters Pt3−5 are determined using far-infrared multiple photon dissociation spectroscopy of their argon complexes combined with density functional theory calculations. The clusters are found to have compact structures, and Pt4 and Pt + 5 already favor three dimensional geometries, in contrast to a number of earlier predictions. Challenges in applying density functional theory to 3rd row transition metal clusters are addressed. Preliminary calculations suggest that the effects of spin-orbit coupling do not change the favoured lowest-energy isomers.