第一性原理对Al_mSi_n(m=1,2;n=1～6)团簇结构与性质的研究

本文运用第一性原理对Al_mSi_n（m=1,2;n=1～6）团簇的结构与性质进行了研究.在BLYP的水平上进行了结构优化和频率分析,得到了团簇的最低能量结构.同时计算和讨论了A1_msi_n团簇的束缚能、总能的二阶能量差分和分裂能以及费米能随原子数的变化.研究结果表明:Al_mSi_n团簇在m+n<4时的几何结构是平面结构,从4个原子开始转为空间的立体结构;除AlSi₃和Al₂Si₂团簇外,Al_mSi_n（m=1,2;n=1～6）团簇的束缚能随原子数增加而减小;分析A1_mSi_n（m=1,2;n=1～6）团簇的二阶能量差分和分裂能发现:在m+n=3,5时,团簇都出现较稳定的结构.

First-principles study of structures and properties of AlmSin(m=1, 2; n=1-6) clusters

Structures and properties of AlmSin(m=1, 2; n=1-6) clusters have been studied by first principles. We obtained the most stable isomers of AlmSin(m=1, 2; n=1-6) clusters by means of structural optimization and frequency at the BLYP level. Meanwhile, we also calculated the second order differences, fragmentation energy, binding energy, and Fermi energy with a change of the atoms. The results show that the geometric structures of AlmSin clusters are planar construction when m plus n less than 4, then change from plane into three-dimensional structure of space with the increasing number of atom. The binding energies of the clusters AlmSin(m=1, 2; n=1-6)decrease as the number of atoms increases, excepting for the cluster AlSi3 and Al2Si2. By analyzing the second-order energy difference of AlmSin(m=1, 2; n=1-6)clusters and the fragmentation energy, it is found that the clusters have a more stable structure when m add n is three or five.