团簇Ti_3Al_3的成键及结构稳定性研究

Study on bonding properties and structure stability of cluster Ti_3Al_3

采用密度泛函理论方法,通过B3LYP/lanl2dz对团簇Ti_3Al_3的所有可能的构型进行优化计算,最终得到11种能够稳定存在的构型。从结构能量角度分析,发现四重态能量低于相应二重态的能量,四重态比二重态更稳定。这些构型的结合能EBE均大于零且吉布斯自由能变△G均小于零,可以自发反应。在所有构型中1(2)、1(4)是不同重态的相同构型,能量最低,结合能EBE最大,吉布斯自由能变△G最小,因此1(2)、1(4)最易发生自发反应且稳定性最好。从键长、键级角度分析,Ti-Ti、Ti-Al键对团簇Ti_3Al_3的稳定性起主要作用。

Based on density functional theory(DFT),all the possible configurations of cluster Ti3Al3 were calculated and optimized at B3LYP/Lan12dz level and finally11stable configurations were obtained.From the view point of structural energy,it is found that the energy of the quadruplet state is lower than that of the corresponding doublet state and thus the quadruplet state is more stable than the doublet state.The binding energy(EBE)of these structures is positive and the Gibbs free energy change(△G)is negative,so that the reactions are spontaneous.Among all the configurations,1(2)and 1(4),which are the same configurations but in different states have the lowest energy,the highest binding energy and the minimum Gibbs free energy change(△G).Therefore,the reactions forming the configurations 1(2)and 1(4)are the most spontaneous and accordingly they are the most stable.Furthermore,in view of the bond length and order,Ti-Ti and Ti-Al play a major role in the stability of the cluster Ti3Al3.