title: The structural and electronic properties of NbSin-/0(n = 3-12) clusters: anion photoelectron spectroscopy and ab initio calculations.
abstract: Niobium-doped silicon clusters, NbSin-(n = 3-12), were generated by laser vaporization and investigated by anion photoelectron spectroscopy. The structures and electronic properties of NbSin-anions and their neutral counterparts were investigated with ab initio calculations and compared with the experimental results. It is found that the Nb atom in NbSin-/0prefers to occupy the high coordination sites to form more Nb-Si bonds. The most stable structures of NbSi3-7-/0are all exohedral structures with the Nb atom face-capping the Sinframeworks. At n = 8, both the anion and neutral adopt a boat-shaped structure and the openings of the boat-shaped structures remain unclosed in NbSi9-10-/0clusters. The most stable structure of the NbSi11-anion is endohedral, while that of neutral NbSi11is exohedral. The global minima of both the NbSi12-anion and neutral NbSi12are D6hsymmetric hexagonal prisms with the Nb atom at the center. The perfect D6hsymmetric hexagonal prism of NbSi12-is electronically stable as it obeys the 18-electron rule and has a shell-closed electronic structure with a large HOMO-LUMO gap of 2.70 eV. The molecular orbital analysis of NbSi12-suggests that the delocalized Nb-Si12ligand interactions may contribute to the stability of the D6hsymmetric hexagonal prism. The AdNDP analysis shows that the delocalized 2c-2e Si-Si bonds and multicenter-2e NbSinbonds are important for the structural stability of the NbSi12-anion.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. xuhong@iccas.ac.cn zhengwj@iccas.ac.cn and University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Sheng-Jie
authors.initials: SJ
authors.lastname: Lu
authors.affiliation: Institute of Molecular Science, Shanxi University, Taiyuan 030006, China.
authors.forename: Guo-Jin
authors.initials: GJ
authors.lastname: Cao
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. xuhong@iccas.ac.cn zhengwj@iccas.ac.cn and University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Xi-Ling
authors.initials: XL
authors.lastname: Xu
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. xuhong@iccas.ac.cn zhengwj@iccas.ac.cn and University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Hong-Guang
authors.initials: HG
authors.lastname: Xu
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. xuhong@iccas.ac.cn zhengwj@iccas.ac.cn and University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Wei-Jun
authors.identifier: http://orcid.org/0000-0002-9136-2693
authors.initials: WJ
authors.lastname: Zheng