Structures and magnetic properties of small and Con−1Cr+ (n = 3–5) clusters

Abstract

Small cobalt clusters and their single chromium atom doped counterparts Con−1Cr+ (n = 3–5) were studied mass spectrometrically by measuring the infrared multiple photon dissociation (IRMPD) spectra of the corresponding argon tagged complexes. The geometric and electronic structures of the and Con−1Cr+ (n = 3–5) clusters as well as their Ar complexes were optimized by density functional theory (DFT) calculations. The obtained lowest energy structures were confirmed by comparing the IRMPD spectra of and (n = 3–5, m = 3 and 4) with the corresponding calculated IR spectra. The calculations reveal that the doped Con−1Cr+ clusters retain the geometric structures of the most stable clusters. However, the coupling of the local magnetic moments within the clusters is altered in a size-dependent way: the Cr atom is ferromagnetically coupled in Co2Cr+ and Co3Cr+, while it is antiferromagnetically coupled in Co4Cr+.