Fengli Liu

Geometrical and electronic structures of the SnnCl and SnnCl- (n = 1-6) clusters

Theoretical studies of the structures of Sn n Cl and Sn n Cl− (n = 1–6) clusters have been carried out using density functional theory methods. The geometric structure of each unit is optimized at the B3LYP level, employing the LANL2DZpd for tin and DZP++ for chlorine basis sets. The resulting total energies, fragmentation energies and equilibrium geometries of chlorine–tin clusters are presented and discussed, together with natural populations and natural electron configurations. The impact on internal electron transfer between the (Sn n ) subsystem and Cl atom in Sn n Cl− (Sn n Cl) clusters is investigated. In addition, theoretical results for the electron affinities of Sn n Cl (n = 4–6) clusters are in good agreement with experimental results available.

An Ab initio pseudopotential study of MnPo (M = Cu, Ag, Au; n = 1, 2) systems

The small coinage-metal polonium compounds MPo and M2Po, (M = Cu, Ag, Au) are studied at Hartree–Fock (HF), second-order Moller–Plesset perturbation theory (MP2), and coupled cluster method CCSD(T) levels using relativistic and non-relativistic pseudopotentials. The calculated geometries indicate that the M2Po (M = Cu, Ag, Au) systems have bent structures of ~64° angles. Electron correlation corrections to the bond length M–Po are extremely small, but to the bond angle M–Po–M are significant; in general, it was reduced from 86° to 64°. Relativistic effects on bond angle are small, but on bond length are distinct. Both electron correlation effects and relativistic effects are essential to determine the geometry and relative stability of the systems. It can be predicted that Au2Po is relatively stable compared with Ag2Po.

Ab Initio Study of Structure and Stability of M2Al2 (M = Cu, Ag, and Au) Clusters

Coinage metal aluminium clusters M2Al2 (M = Cu, Ag, and Au) were studied by Hartree–Fock (HF) and second-order Moller–Plesset perturbation theory (MP2) with pseudopotentials. It was found that the butterfly structure with C2v (1A1) symmetry is more stable than the planar structure, and Au2Al2 is the most stable of the title species. The binding energies and the highest occupied molecular orbital and the lowest unoccupied molecular orbital (HOMO–LUMO) gap are evaluated, which indicates that doping clusters M2Al2 are more stable than the pure clusters M4 (M = Cu, Ag, and Au). Electron correlation and relativistic effects stabilize the present species.