Nature of Valence Transition and Spin Moment in AgnV+ Clusters

作者：Medel Victor M; Reber Arthur C; Chauhan Vikas; Sen Prasenjit; Koester Andreas M; Calaminici Patrizia; Khanna Shiv N

来源：Journal of the American Chemical Society, 2014, 136(23): 8229-8236.

DOI：10.1021/ja412064c

Evolution in the atomic structure, bonding characteristics, stability, and the spin magnetic moment of neutral and cationic AgnV clusters has been investigated using first-principles density functional approach with gradient corrected functional. It is shown that at small sizes, the V 4s states hybridize with Ag states to form IS and IP like superatomic orbitals, whereas the 3d states are localized on V giving the V atom an effective valence of 1 or 2. Starting from Ag8V+, the V 3d states begin to participate in the bonding by hybridizing with the nearly free electron gas to form ID superatomic orbitals increasing the V atom effective valence toward 5. For the cationic clusters, this changing valence results in three shell closures that lead to stable species. These occur for cationic clusters containing 5,7, and 14 Ag atoms. The first two stable species correspond to filled 1S and IP shells in two and three dimensions with a valence of 2 for V, whereas the closure at 14 Ag atoms correspond to filled IS, 1P, and ID shells with V site exhibiting a valence of 5. The transition from filled IS and IP shells to filled 1S, IP, and ID shells is confirmed by a quenching of the spin magnetic moment. The theoretical findings are consistent with the observed drops in intensity in the mass spectrum of AgnV+ clusters after 5,7, and 14 Ag atoms.

• 出版日期2014-6-11