The Theoretical Studies On Structures And Performances Of Nin And NinAl (n=2-13)clusters

Transition metal clusters have become one of the most attractive areas of current research due to their very excellent performances on physical properties, chemical properties, magnetic and catalytic aspects, which originate from their unique geometrical structures. At present, it has attracted the attention of the researchers. Nickel clusters, one kind of the transition metal clusters, are widely used in catalytic reaction and magnetic materials because of their unique geometrical structures and delocalized d electrons. In recent years, studies on the experimental and theoretical aspects of nickel clusters and its alloy clusters are increasing day by day.This article calculates and analyzes the structures and performance of Nin and NinAl (n=2-13)clusters through the Density Functional Theory and Gaussian03software, the main content and the results are as follows:(1)We calculate the binding energies, the magnetic moment and the ionization potential of nickel clusters through various methods of the Gaussian03program and then analyze on the basis of the experimental data and other methods reported in the previous literatures. Theoretical results show that BPW91/Lanl2dz is the best level for nickel clusters research. The ground state configurations and electronic structure properties of Nin (n=2-13) clusters are investigated in the BPW91/Lanl2dz level of DFT method and explain the paramagnetic and diamagnetic to the influence of the magnetic moment after different nickel cluster molecular hybridization by the molecular orbital diagram.(2) We make the ground state configurations of NinAl (n=1-8,12) clusters in BPW91/Lanl2dz/6-31G(d) level and find that Al atom adsorb in lateral of nickel clusters priority. The adsorption model is point instead. In addition, we infer that Ni5Al is the most stable cluster in NinAl (n=1to8,12) clusters through the average binding energy and HOMO-LUMO gap analysis of doped clusters. The cluster is the most stable when the contents of Al is16.7%through analysizing the fragmentation energy, the second difference in energy and the ionization potential. The magnetic moment trend and the natural charge distribution of bimetallic clusters are agree with the molecular orbital diagram. Compared with monometallic nickel clusters, the magnetic moments of NinAl(n=1-8,12) clusters are reduced because of the diamagnetism of Al atom and s-p-d hybridization of Ni-Al.(3) We make the ground state configurations of NinAl-H2(n=1-6)clusters in BPW91/Lanl2dz/6-31G(d) level and find that hydrogen molecular adsorb in the edge of the cluster dissociativly. NBO analysis and Millikan charge analysis illustrate the internal orbit hybrid phenomenon of hydrogen adsorbed clusters:Electrons mainly transfer from3s orbit of Al atom to3d orbit of Ni atom and1s orbit of H atom. It can be seen from the parameters of chemical adsorption energy and the trend diagram that the chemical activity of Ni3Al-H2cluster is strongest and Ni5Al-H2cluster is most weak, respectively.To sum up, BPW91/Lanl2dz level is used for the first time to study the physical and chemical properties of Nin and NinAl (n=2-13) clusters. The accuracy of the level has important reference significance for nickel clusters research and provides a certain theoretical basis for seeking new functional materials in the future.