Structure determination of (Fe3O4)n+(n = 1 − 3) clusters via DFT

In virtue of the particle swarm optimization (PSO) algorithm, the global minimum candidate structures with the lowest energy for [Formula: see text] clusters were obtained by first-principles structural searches. The geometric structures and spin configurations of three cationic [Formula: see text] clusters have been identified for the first time by comparing the experimental IR spectra with the calculated results from density functional theory by using different exchange-correlation functionals. It is found that the lowest energy structures of these clusters are of a shape of hat, boat and tower, respectively, with a ferrimagnetic arrangement of spins, and M06L functional is more suitable for [Formula: see text] clusters than other ones.