The Research For Geometry,Potential Function,Energy Level Distribution And Electronic Properties Of Au,Cu,Y Micro-clusters

The nanometer material and technology is the most alive subject branch, with very abundant research connotation in the nanometer of scientific and technological fields, and nanometer material is occupying central position in research application of the whole new material. The atomic cluster is one of the elementary cell which forms nanometer body, membrane, multilevel membrane and nanometer structure, so the theoretical research for ground-state structures, energy level distribution and electronic properties of its is one of the important subject in the design of micro structure of new material, and has great signification in "custom-made" new material with specific performance. In mis paper, the molecular structure and potential energy function of small cluster of gold, copper and yttrium have been calculated by use of the density function theory (DFT) Becke 3LYP method with relativistic effective core potential (RECP) and Gaussian98W program. On this basis, the ground-state structure, energy level distribution and the electronic properties of cluster of An, ( n=2-9), Yn (n=2-8), and AunY( n=l-9) are researched systematically. It is the first time to use the " soft ball model" theory of duster to explain the structure of Yn ( n=2-8) ,and adopt the "shell model" theory and assigning equally delocalize valence electrons of cluster to elucidate the relativity of structure and stability of doped cluster of noble metal Au,,Y(l -9) successfully.The cluster molecules structures for Au2 Cu2 Y2 AuY AuCu Au and Au Y are calculated At the base of the atomic and molecular reaction statics, according to the grouptheory principle of electron state construction of molecule, the electronic state of the small cluster molecule gold, copper and yttrium are determined. Results show that tire ground electronic states for Au2, AuY, Au3 and Au2Y are X , and respectively, and the corresponding reasonable dissociation limits.The Murrell-Sorbie potential energy function curves of diatomic molecule of Au2 Cu2 Y2 AuY and AuCu have been obtained, then the spectral datum and force constants have been derived.. The analytic potential energy functions for ground states of Au (X2 B 2) and Au2 Y (X2A1) molecules are derived by many-boy expansion method, then their equivalence potential energy curves are drawn, which show the stable structure characteristics and energy relation of Au3and Au2 Y, and discuss the static characteristic of potential energy sections of Au2 (X ) +Au and Au2 (X ) +Y (2Dg) , There is no saddle point on these reaction channels, namely no energy threshold appears.It's the first time to use the B3LYP/LANL2DZ method of density function theory to research the stability of the ground state structure of cluster Au,, (n=2-9) Y n (n=2-8) and Aun Y (n=l-9), the Fermi level, ionization potentials and electron affinities and so on, systematically.The research result of cluster An, (n=2-9) indicate that the "odd-even" alternations and "magic numbers" effect exist in all of them, the Aun, cluster demonstrates: higher stability and ionization potentials, lower electron affinities and the Fermi levels while n is even number; or vice versa while n is odd. The ionization potentials are calculated of cluster Au,, (n=2-9) with this method and the results are more reasonable agreement with the experiment than the experiential genetic simulation method. The ground-state structure of the gold micro-clusters are planar, and electron s plays a controlling role, it is similar to alkali metal and other noble metal cluster, the change of 2-3D structure is from AU7. In the aspect of stability of cluster, the general trend of average atomization energies of ground-states from cluster Au2 to Au9 increases monotonically, so does average coordination number, the stability from cluster Au2 to Au9 strengthens gradually, and Au2 and Au8 are especially steady, all of these can be well explained by the "shell model", the valence electron of Au2 and Au8 are 2,8, just fill-up the levels of the Wood-Saxon spherical symmetrical potential, that is,ls(2elec...