The structures of Al12C and Al12C^- clusters are studied, by using the density functional theory. We find that the charging on the icosahedral Al12C cluster drives the carbon atom from the center of the cluster to its surface. The optimized ground state structure of Al12C^- cluster has a low symmetry, in agreement with experimental observation.

Li S. F.;Gong X. G.

Physical Review B Condensed Matter and Materials Physics

2004

(Chemical Equation Presented) A heart of gold: The structure of the Au 32^- cluster has been elucidated by comparison of the results from photoelectron spectroscopy with those from theoretical calculations. Although DFT calculations suggest a high-symmetry hollow-cage structure (Ih, left) to be the lowest in energy at 0 K, the spectrum calculated for a low-symmetry (C1, right) distorted cage containing three Au atoms inside agrees best with the experimental results. © 2005 Wiley-VCH Verlag GmbH & Co. KGaA.

Ji Min;Gu Xiao;Gong Xingao;Li Jun;Li Xi;Wang Lai-Sheng

Angewandte Chemie International Edition

2005

Based on the density functional theory with gradient corrected exchange-correlation potential, we have studied the atomic structures and electronic properties of Al7IN (N = 1, 2, 3) and Al 13I clusters. The atomic structure of Al7 is not significantly changed by doping three iodine atoms. However, the adsorption positions of iodine atoms are dependent on the charge state of Al 7In cluster. Analyzes of the electronic structure of Al7In- cluster shows that some of the electrons are transferred to iodine atom, although most electrons in the highest occupied molecular orbits distribute around the aluminum atoms. © 2005 Elsevier B.V. All rights reserved.

Wei Shi-Hao;Huang Li;Ji M.;Gong X. G.

Chemical Physics Letters

2006

Ab initio calculations have been performed on the electronic structures for some semiconductor-metal alloy clusters Aun Sim (n,m=1-4), upon which very stable cubiclike clusters X4 Y4 (X=Cu,Ag,Au,Ti; Y=C,Si) have been found. The calculations show that relativistic effect as well as the ionic bonds may together play the key role in the cubic structures. The large highest occupied lowest unoccupied molecular orbital gaps (0.8-2.24 eV) make them attractive for optoelectronic applications and the perfect cubic structures make some of them desirable for cluster-assembled materials, such as one-dimensional nanotubes. © 2006 The American Physical Society.

Li S. F.;Xue Xinlian;Jia Yu;Zhang Mingfeng;Zhao Gaofeng;Gong X. G.

Physical Review B Condensed Matter and Materials Physics

2006

The magnetic properties of small CunTM clusters (n = 3-7, 12, TM = Ru, Rh, Pd) have been studied using a linear combination of the atomic orbital approach with the density functional formalism, and the Kohn-Sham equation is solved self-consistently using the discrete variational method (DVM). It is found that the magnetic moments of Rh in the D3h structure and Ru in the Td structure are quenched to zero (we call this phenomenon the symmetry-quenching effect). It is also found that Ru and Rh are magnetic (except for symmetry-quenching), and Pd is nearly nonmagnetic. The effects of symmetry, coordination number and atomic distance on the magnetic moments of 4d impurities are discussed. © 1995.

Sun Q.;Wang G. H.;Gong X. G.;Zheng Q. Q.

Physics Letters A

1995

Li S. F.;Xue Xinlian;Jia Yu;Zhao Gaofeng;Zhang Mingfeng;Gong X. G.

Physical Review B Condensed Matter and Materials Physics

2006

We calculate systematically the absolute volume deformation potential (AVDP) of the Γ8v valence band maximum (VBM) and the Γ6c conduction band minimum (CBM) states for all group IV, III-V, and II-VI semiconductors. Unlike previous calculations that involve various assumptions, the AVDPs are calculated using a recently developed approach that is independent of the selection of the reference energy levels. We find that although the volume deformation potentials of the CBM state are usually large and always negative, those of the VBM state are usually small and always positive. The AVDP of the VBM state decreases as the p-d coupling increases, e.g., in the II-VI compounds. The AVDP of CBM decreases as the ionicity increases. Our calculated chemical trends of the AVDPs are explained in terms of the atomic orbital energy levels and coupling between these orbitals. © 2006 The American Physical Society.

Li Yong-Hua;Gong X. G.;Wei Su-Huai

Physical Review B Condensed Matter and Materials Physics

2006

Ab initio theoretical calculations have been performed to study the reaction of O2 with Ban (n=2,5) clusters. Our results show that O2 can easily chemisorb and dissociate on small Ban clusters and there is no obvious energy barrier in the process of the dissociation. The local magnetic moment contributed by oxygen must vanish during the intermediate states before the O2 dissociation. Correspondingly, local magnetic moment only decreases from 2 μB to about 1 μB if O2 molecularly adsorbs onto Ba5 cluster. The electronic structure analysis indicates that the charge transfer from Ban cluster to O2 as well as the orbital hybridization between the cluster and the oxygen molecule may play a key role in O2 dissociation. © 2006 American Institute of Physics.

Li S. F.;Xue Xinlian;Jia Yu;Chen G.;Yuan D. W.;Gong X. G.

Journal of Chemical Physics

2006

First-principles calculations are performed to study the interaction of cluster Au 32 with small molecules, such as CO, H 2 , and O 2 . The cagelike Au 32 (I h ) shows a higher chemical inertness than the amorphous Au 32 (C 1 ) with respect to the interaction with small molecules CO, H 2 , and O 2 . H 2 can only be physically adsorbed on Au 32 (I h ), while it can be dissociatively chemisorbed on Au 32 (C 1 ). Although CO can be chemically adsorbed on Au 32 (C 1 ) and Au 32 (C 1 ) with one electron transferred from Au 32 to the antibonding π* orbit of CO, it is bound more strongly on Au 32 (C 1 ) than on Au 32 (I h ). Spin polarized and spin nonpolarized calculations result almost identical ground state structures of Au 32 (I h )-O 2 and Au 32 (C 1 )-O 2 , in which O 2 is dissociatively chemisorbed. © 2006 American Institute of Physics.

Wang Yao;Gong X. G.

Journal of Chemical Physics

2006

We have studied the stable geometries of Nin clusters using the first principles method with ultrasoft pseudopotentials. It is found that the ground state structures of Nin (n = 10 ∼ 27, 41 ∼ 56) are icosahedron-like, while Ni13 and Ni55 are perfect icosahedra, in agreement with experimental results. For Nin (n = 28 ∼ 40), no simple growth mode can be found even though some of them display certain symmetry. The size dependence of magnetic moments calculated with these ground state structures nicely reproduces experimental trend. In general, we found two peaks around n = 15 ∼ 20 and n = 35 ∼ 40, and three dips at n = 13, 34, 55. The deviation between the calculated results and experimental data, assigned as the orbital magnetic moment, decreases monotonically as the cluster size increases. © 2006.

Yao Y. H.;Gu X.;Ji M.;Gong X. G.;Wang Ding-sheng

Physics Letters Section A General Atomic and Solid State Physics

2007