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>Electronic structures of tetrahedral iron, cobalt, and nickel clusters. Partial quenching of magnetism in partially carbonylated derivatives
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Electronic structures of tetrahedral iron, cobalt, and nickel clusters. Partial quenching of magnetism in partially carbonylated derivatives
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机译：Electronic structures of tetrahedral iron, cobalt, and nickel clusters. Partial quenching of magnetism in partially carbonylated derivatives
Spinhyphen;polarized calculations of tetrahedral Fe4, Ni4, and Co4clusters have been performed by the selfhyphen;consistent field discrete variationalXagr; method. Partially carbonylatedC3vclusters Co4(mgr;minus;CO)3and (OC)3CoCo3(mgr;minus;CO)3have also been examined to explore how magnetic moments vary with cluster coordination environment. The bare tetrahedral clusters are magnetic containing 12, 6, and 2 unpaired electrons for Fe4, Co4, and Ni4, respectively. Exchange splittings also decrease (2.68, 1.60, and 0.56 eV) along this series. Analysis of density of states plots for these clusters supports the notion that 4sand 4pmixing into the metaldband yields hybrid orbitals better suited for metalndash;metal bonding. Electronic transitions are predicted to occur in the near IR absorption spectra of the M4clusters, a region yet to be studied experimentally. Calculations forC3vCo4(mgr;minus;Co)3yield six unpaired electrons with a large spin density on the unligated apical cobalt. In (OC)3CoCo3(mgr;minus;CO)3, where the apical cobalt is coordinately saturated, all the spin density (four unpaired electrons) is localized in the basal plane. Bridging CO groups in the basal plan are antiferromagnetically coupled to cobalt.
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