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A systematic study of the X2Aun(X = La, Y, Sc;n= 1–9) clusters are performed by using the density functional theory at TPSS level. The structures, stabilities, electronic, and magnetic properties are investigated in comparison with pure gold clusters. The results show that the transition points of the doped clusters from two-dimensional to three-dimensional structure are obviously earlier than gold clusters. The impurity X atoms tend to occupy the most highly coordinated position and form the largest probable number of bonds with gold atoms. In addition, the impurity atoms can strongly enhance the stabilities of gold clusters. It indicates that the impurity atoms dramatically affect the geometries and stabilities of the Aunclusters. The highest occupied molecular orbital–lowest occupied molecular orbital gap, vertical ionisation potential, and chemical hardness show that the X2Au6clusters have higher stabilities than the others. In La2Au1–9, Y2Au1–7, and Sc2Au1–4clusters, the charges transfer from X atoms to the Aunframes. The total magnetic moments of X2Aunclusters exist distinctly odd–even alternation behaviours except for La2Au4and Sc2Au4clusters. [ABSTRACT FROM AUTHOR]

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 CaAu ( n = 1-9) and pure gold Au ( n ≤ 11) clusters. The optimized geometries show that the most stable isomers for CaAu clusters have 3D structure when n > 2, and that one Au atom capping the CaAu structure for different-sized CaAu ( n = 1-9) clusters is the dominant growth pattern. The average atomic binding energies and second-order difference in energies show that the CaAu isomer is the most stable among the CaAu clusters. The same pronounced even-odd alternations are found in the HOMO-LUMO gaps, VIPs, and hardnesses. The polarizabilities of the CaAu 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. [ABSTRACT FROM AUTHOR]

Ab initio methods based on density functional theory at BP86 level were applied to the study of the geometrical structures, relative stabilities, and electronic properties of small bimetallic BeAu ( n = 1-9) clusters. The optimized geometries reveal that the most stable isomers have 3D structures at n = 3, 5, 7, 8, and 9. Here, the relative stabilities were investigated in terms of the averaged atomic binding energies, fragmentation energies and second-order difference of energies. The results show that the planar BeAu structure is the most stable structure for BeAu clusters. The HOMO−LUMO gap, vertical ionization potential, vertical electron affinity and chemical hardness exhibit a pronounced even-odd alternating phenomenon. In addition, charge transfer and natural electron configuration were analyzed and compared. [ABSTRACT FROM AUTHOR]

The geometric structures, relative stabilities, and electronic properties of a series of tetra-aluminum oxide clusters, [image omitted] ( [image omitted], [image omitted]), were systematically investigated using density functional theory calculations at the B3LYP level. The optimized geometries reveal a structural transition from a two-dimensional to a three-dimensional structure for n ≤5 for the neutral species, but the three-dimensional structures are preferable for all negative clusters with the exception of [image omitted]. The dissociation energy, the second difference energy and the highest occupied-lowest unoccupied molecular orbital gaps as a function of the cluster size exhibit a significant even-odd alternation phenomenon. It is found that the neutral [image omitted] cluster is relatively stable and exhibits strong chemical stability. Furthermore, the calculated (vertical and adiabatic) electron detachment energies are also compared with previous experimental data obtained from photoelectron spectra. [ABSTRACT FROM AUTHOR]

Abstract: Based on the complete energy matrix approach, the local structure and zero field splitting (ZFS) parameter for ZnSiF6·6H2O:Ni2+ (V2+) systems are theoretically studied for 3d n (n =3, 8) ions in trigonal symmetry at different pressure. In this approach, the contributions from the admixture of d orbitals of the central ions with the p orbitals of the ligands are considered. In addition, the relationships between the ZFS parameter D and the pressure P as well as the local structure parameter θ are discussed. The effects of the average parameter ζ 1 and the different parameter ζ 2 on the ZFS parameter D are analyzed. [Copyright &y& Elsevier]

Abstract: By using the complete energy matrix and taking into account the contributions from the spin orbit coupling of the central ions as well as those of the ligand ions, the local structure distortion have been studied for Cr3+ ions doping in KAl(MoO4), Y3Ga5O12, Y3Al5O12 and ZnAl2O4 crystals. The results show that the local structure exhibit elongation distortions for the doped systems. Moreover, the influence of the local structure parameter θ on the EPR parameter D are studied. The relationships between D and (ζ, ζ′) as well as the average parameter ζ 1 () and the different parameter ζ 2 () are discussed. [ABSTRACT FROM AUTHOR]