| Abstract
| - The structure and properties of small neutral and cationic CrGen0,+ clusters, with n from 1 to 5, were investigatedusing quantum chemical calculations at the CASSCF/CASPT2 and DFT/B3LYP levels. Smaller clusters preferplanar geometries, whereas the lowest-lying electronic states of the neutral CrGe4, CrGe5, and cationic CrGe5+forms exhibit nonplanar geometries. Most of the clusters considered prefer structures with high-spin groundstate and large magnetic moments. Relative to the values obtained for the pure Gen clusters, fragmentationenergies of doped CrGen clusters are smaller when n is 3 and 4 and larger when n = 5. The averaged bindingenergy tends to increase with the increasing number of Ge atoms. For n = 5, the binding energies for Ge5,CrGe5, and CrGe5+ are similar to each other, amounting to ∼2.5 eV. The Cr atom acts as a general electrondonor in neutral CrGen clusters. Electron localization function (ELF) analyses suggest that the chemical bondingin chromium-doped germanium clusters differs from that of their pure or Li-doped counterparts and allowthe origin of the inherent high-spin ground state to be understood. The differential ΔELF picture, obtained inseparating both α and β electron components, is consistent with that derived from spin density calculations.For CrGen, n = 2 and 3, a small amount of d−π back-donation is anticipated within the framework of theproposed bonding model.
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