Density Functional Study Of Al-doped Ti Clusters

In recent years, the design of new functional materials bycomputer simulations, i.e., computational material science, has beenone of important methods in the design and analysis of properties.Alloy clusters of transition metal (TM), for its very interestingproperties and potential application, have been attractedconsiderable research interests in recent years, and achievedsplendid results. However, studies of titanium cluster are ratherscarce compared with other TM clusters, not to mention itsmetal-doped clusters. In the paper, we have systematically studiedthe electronic structure of the small titanium clusters TiNAl (N=1~13)by using density functional theory (DFT), and revealed inmicrocosmic that the structures and bonding nature of these clusterstake place a transition as the size of clusters increases. The paper is structured as follows. In the introduction, thethinking,method and purpose of study are briefly introduced. Firstly, the density functional theory (DFT), local (spin) densityapproximation (L(S)DA) and generalized gradient approximation(GGA) are described in detail. The discrete veriational method(DVM) and the package of quantum chemical ab initio calculationsfor molecules and clusters are introduced. In chapter II and III, we study the equilibrium geometries ofTiNAl clusters optimized by using ab initio calculations. Base onthese stable structures, the stability, magic number, and electronicstructures are also discussed. It is found that there are transitions,such as the structure, valence and bonding nature, in these clusters. In chapter IV, using the DVM, we study density of state andmagnetic moments of the TiNAl clusters. It is found that the向 君 湘潭大学硕士论文structure and size of cluster have a significant effect on the magneticmoment. In the last chapter, summarizations of our works as well assome prospects are given, in particularly on the titanium-oxideclusters.