Ferrimagnetic cagelike Fe4O6 cluster: Structure determination from infrared dissociation spectroscopy

Abstract

Cationic iron-oxide clusters of several sizes and stoichiometries have been synthesized and studied isolated in the gas phase. Vibrational spectra of the clusters have been measured using resonant IR-induced dissociation of Fe nOm+2+ → FenOm+ + O2 in the 250-1250 cm-1 range. Density-functional theory was used to investigate the geometry and spin configuration of the representative Fe4O60/+ cluster. Its lowest-energy state was found to be an almost tetrahedral cagelike structure with a ferrimagnetic arrangement of spins, resulting in total cluster spin of S=5 for the neutral cluster. These results were confirmed for Fe 4O6+ by the comparison of the calculated infrared spectrum to the experimentally obtained one. © 2010 The American Physical Society.