Influence of Single Impurity Atoms on the Structure, Electronic, and Magnetic Properties of Ni5 Clusters
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- 作者：Petko St. Petkov ; Georgi N. Vayssilov ; Sven Krü ; ger ; Notker Rö ; sch
- 刊名：Journal of Physical Chemistry A
- 出版年：2007
- 出版时间：March 22, 2007
- 年：2007
- 卷：111
- 期：11
- 页码：2067 - 2076
- 全文大小：261K
- 年卷期：v.111,no.11(March 22, 2007)
- ISSN：1520-5215
文摘
With a gradient-corrected density functional method, we have studied computationally the influence of singleimpurity atoms on the structure, electronic, and magnetic properties of Ni5 clusters. The square-pyramidalisomer of bare Ni5 with six unpaired electrons was calculated 23 kJ/mol more stable than the trigonal bipyramidin its lowest-energy electronic configuration with four unpaired electrons. In a previous study on the clusterNi4, we had obtained only one stable isomer with an O or an H impurity, but we located six minima for ONi5and five minima for HNi5. In the most stable structures of HNi5, the H atom bridges a Ni-Ni edge at thebase or the side of the square pyramid, similarly to the coordination of an H atom at the tetrahedral clusterNi4. The most stable ONi5 isomers exhibit a trigonal bipyramidal structure of the Ni5 moiety, with the impuritycoordinated at a facet, (
3-O)Ni5, or at an apex edge, (-O)Ni5. We located four stable structures for a Cimpurity at a Ni5 cluster. As for CNi4, the most stable structure of the corresponding Ni5 complex comprisesa four-coordinated C atom, (4-C)Ni5, and can be considered as insertion of the impurity into a Ni-Ni bondof the bare cluster. All structures with C and five with O impurity have four unpaired electrons, while thenumber of unpaired electrons in the clusters HNi5 varies between 3 and 7. As a rough trend, the ionizationpotentials and electron affinities of the clusters with impurity atoms decrease with the coordination numberof the impurity. However, the position of the impurity and the shape of the metal moiety also affect theresults. Coordination of an impurity atom leads to a partial oxidation of the metal atoms.
3-O)Ni5, or at an apex edge, (-O)Ni5. We located four stable structures for a Cimpurity at a Ni5 cluster. As for CNi4, the most stable structure of the corresponding Ni5 complex comprisesa four-coordinated C atom, (4-C)Ni5, and can be considered as insertion of the impurity into a Ni-Ni bondof the bare cluster. All structures with C and five with O impurity have four unpaired electrons, while thenumber of unpaired electrons in the clusters HNi5 varies between 3 and 7. As a rough trend, the ionizationpotentials and electron affinities of the clusters with impurity atoms decrease with the coordination numberof the impurity. However, the position of the impurity and the shape of the metal moiety also affect theresults. Coordination of an impurity atom leads to a partial oxidation of the metal atoms.