We report the results on the structural and electronic properties of a Ga13 cluster carried out by the ab-initio molecular dynamics method. We found an icosahedron with some Jahn-Teller distortion to be the lowest energy structure for the Ga13 cluster. The charge density in the cluster is much lower than that in the bulk α-Ga, which implies that the bonding is still metallic. © 1995.

Gong X. G.;Zheng Q. Q.;Han R. S.

Solid State Communications

1995

The magnetic properties of small Ag n TM clusters (n = 3-7, 12; TM = Ru, Rh, Pd) have been studied using a linear combination of atomic orbitals approach with the density functional formalism, and the Kohn-Sham equation is solved self-consistently with the discrete variational method (DVM). The symmetry-quenching effect is found that the magnetic moments of Rh in D 3h , structure and Ru in T d structure are quenched to zero. Meanwhile, it is 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 moment of 4d impurities are discussed.

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

Solid State Communications

1996

The magnetic properties of Fe3 TMB clusters (TM: 3d transition metal) are studied systematically using the discrete-variational local-spin-density-functional method; the equilibrium bond length, binding energy, ionization potential and magnetic moments are determined. It is found that the magnetic moment of Fe displays an even-odd alternation upon changing the atomic number Z of the TM atom, larger moment of Fe for the even Z and smaller for the odd. If the TM is still Fe, the moment of the host Fe is the largest, the next largest is Ni but not Co as in Fe60TM20B amorphous alloys. Sc, Ti, V and Cr are antiferromagnetically coupling to Fe moment, the rest are coupling ferromagnetically. Fe3MnB cluster has the largest average magnetic moment, it is expected to synthesize a new type of nanostructured magnetic material with this kind of clusters.

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

Physica B Condensed Matter

1996

The equilibrium structures and dynamical properties of neutral and ionized SiH5 and Si2H3 have been studied using the ab initio molecular dynamics method. The obtained equilibrium structures are in good agreement with other highly precise methods. In SiH⁺5, we have clearly observed that H2 rotates about the C3 axis. In Si2H⁺3, we have found that H atoms can interchange positions frequently and also the structure changes. The different dynamical behaviors of the Si-H and C-H molecules has been addressed. © 1997 Published by Elsevier Science B.V.

Gong X. G.;Guenzburger D.;Saitovitch E. B.

Chemical Physics Letters

1997

The static and dynamical properties of a highly symmetric cluster on a fcc(111) surface are studied using the molecular-dynamics method. We find that the cluster can only be stable on the surface up to a certain temperature much lower than the melting temperature of the corresponding isolated cluster; the surface can strongly change the thermal properties of the cluster. The fast diffusion of the cluster is attributed to the rolling of cluster as a whole on the surface, and the dependence of diffusion constants on the structural mismatch is also studied.

Sun D. Y.;Gong X. G.

Surface Science

2000

We have studied the atomic structure and the electronic properties of Ba n clusters by the ab initio molecular dynamics method. We find that a structural transition to the bulk-like structure begins at Ba 9 cluster, and the structures of the clusters are transferred to be icosahedral-like around n = 13. The relatively high stability for Ba 4 , Ba 10 and Ba 13 clusters are observed.

Chen G.;Gong X. G.;Liu Z. F.

European Physical Journal D

2001

The electronic structures of the cluster-assembled solid Al12C (Si) are studied by the ab initio method. We find that Al12C (Si) can solidify into a van der Waals solid. The electronic band structures show very weak dispersion. The main features in the electronic structure of cluster are retained in the solid, and an energy gap up to about 1.5eV is observed for Al12C and Al12Si solids.

Quan Hong-Jun;Gong Xin-Gao

Chinese Physics

2000

We have studied the trapping probability of hyperthermal particles impacted on the surface by molecular dynamics simulations. The angle dependence of the trapping probability, the structural factor of the impacted surface and the sputtering yields have been calculated. We find that, for the normal incidence, the trapping probability decreases with the incident energy, while for 45° incidence, the trapping probability shows a non-monotonic behavior in agreement with a recent experiment.

Duan X. M.;Gong X. G.

Physica Status Solidi B Basic Research

2000

By using the molecular dynamics simulation, we have studied the dynamic behaviors of small energetic clusters deposited on the surface. We find that, at incident energy as low as 1.0 eV/atom, the structure of the cluster is destroyed and cluster atoms form an epitaxial layer above the surface. At high energy incidence, the site exchange between cluster atom and surface atom is observed. The effects of the cluster size and orientation are discussed.

Duan Xiang-Mei;Gong Xin-Gao

Chinese Physics Letters

2000

We have carried out a first-principles calculation on the atomic and electronic shell structures for the experimentally characterized Al77. The onionlike Al77 structure can be described by a stable Al13 inner core covered by a two-layer atomic shell. The stability of Al77 is confirmed by structural optimization and electronic structure calculations. The interaction between Al77 and its ligands is found to be ionic like. Our results on the electronic structure provide important information on electronic shell structures in large Al clusters.

Gong X. G.;Sun D. Y.;Wang Xiao-Qian

Physical Review B Condensed Matter and Materials Physics

2000