Cheng-Gang Li

A systematic search for the structures, stabilities, and electronic properties of bimetallic Ca 2 -doped gold clusters: comparison with pure gold clusters

The local meta-GGA exchange correlation density functional (TPSS) with a relativistic effective core potential was employed to systematically investigate the geometric structures, stabilities, and electronic properties of bimetallic Ca2Aun (n = 1–9) and pure gold Aun (n ≤ 11) clusters. The optimized geometries show that the most stable isomers for Ca2Aun clusters have 3D structure when n > 2, and that one Au atom capping the Ca2Aun−1 structure for different-sized Ca2Aun (n = 1–9) clusters is the dominant growth pattern. The average atomic binding energies and second-order difference in energies show that the Ca2Au4 isomer is the most stable among the Ca2Aun clusters. The same pronounced even–odd alternations are found in the HOMO–LUMO gaps, VIPs, and hardnesses. The polarizabilities of the Ca2Aun clusters show an obvious local minimum at n = 4. Moreover, the inverse corrections to the polarizabilities versus the ionization potential and hardness were found for the gold clusters.

Theoretical investigations of the local structure distortion and relationship between the EPR parameter and spin-orbit coupling coefficients for CsCdX3:Ni2+ (X = Cl, Br) systems

The EPR zero-field splitting parameters and structural distortion of Ni2+-doped CsCdX3 (X = Cl, Br) systems have been studied on the basic of 45f × 45 complete energy matrices for a configuration ion in trigonal ligand field, in which the contributions from the spin-orbit coupling coefficients of the central ions and ligands are taken into account simultaneously. It is shown that the local structure exhibits compression distortions for CsCdX3 (X = Cl, Br):Ni2+ systems, and the contribution from the s.o. coupling coefficient of ligands to the covalent effect should not be neglected. Simultaneously, the relationship between the EPR parameter D and the spin-orbit coupling coefficients (ζ, ) as well as the average parameter ζ1( ) and the divergent parameter ζ2( ) have been discussed.

Theoretical Investigations of the Local Structure Distortion and EPR Parameter for Ni2+-doped Perovskite Fluorides

By analyzing the optical spectra and electron paramagnetic resonance parameter D, the local structure distortion of (NiF6)4− clusters in AMF3 (A=K, Rb; M=Zn, Cd, Ca) and K2ZnF4 series are studied using the complete energy matrix based on the double spin-orbit coupling parameter model for configuration ions in a tetragonal ligand field. The results indicate that the contribution of ligand to spin-orbit coupling interaction should be considered for our studied systems. Moreover, the relationships between D and the spin-obit coupling coefficients as well as the average parameter and the divergent parameter are discussed.

The defect structure and EPR parameters for Er3+ in molybdates: a complete energy matrices study

In this paper, we develop a complete energy matrices approach investigating the defect structure and EPR parameters ( , , and ) for Er3+ in molybdates. In this approach, the crystal-field parameters used in the calculations are determined from the superposition model and the structural data for tetragonal distortion. The local distortion angles Δθ = −1.628°, Δθ = −1.843° and Δθ = −2.874° are obtained for Er3+ in SrMoO4, PbMoO4 and CaMoO4 crystals, respectively. Moreover, the influence of the orbital reduction factor k and the local distortion angle Δθ on the EPR parameters is analyzed.