Al^+与乙硫醇团簇的气相化学反应的实验和理论研究

Experimental and Theoretical Study on Gas-Phase Reaction of Aluminum Ion with Ethanethiol Clusters

利用激光溅射 -分子束的方法研究了Al+ 和乙硫醇的气相化学反应 ,结果观察到了Al+ 与 1～ 6个乙硫醇分子形成的团簇离子 .对团簇离子进行了密度泛函理论计算 ,找到了两种类型的异构体Al+ (C2 H5SH) n 和HAl+ SC2 H5(C2 H5SH) n-1 ,计算得到了相应的稳定结构和能量 .分析质谱信号强度 ,结合理论计算结果 ,可推测出实验得到的n =1的产物离子是Al+ (C2 H5SH) .n =2和 3时产物离子开始转变为HAl+ SC2 H5(C2 H5SH) n -1 ,n =4时 ,HAl+ SC2 H5(C2 H5SH) 3 和Al+ (C2 H5SH) 4两种产物离子都存在 ,n≥ 5以后 ,团簇离子Al+ (C2 H5SH) n 开始成为主要的产物离子 .

The gas phase reaction of the singly positive charged aluminum ion with ethanethiol molecule clusters was investigated by the laser ablation molecular beam method. The cluster ions composed of Al + and 1～6 ethanethiol molecules are produced. Density functional calculations on the structures and energetics of the two isomers Al +^(C 2H 5SH) n and HAl +SC 2H 5(C 2H 5SH) n-1 were carried out at B3LYP/6 31+G(d) level to get a qualitative picture of the gross geometries and relative thermodynamic stability of the species. According to the results of our experiment and calculation, it can be presumed that the product ion is Al +(C 2H 5SH) n for n=1. The anomalous increase of the signal for n=2 and 3 stands for a switching regions of the product cluster, and thus these two clusters are both HAl +~SC 2H 5^(C 2H 5SH) n-1. For n=4, both Al +^(C 2H 5SH) 4 and HAl +SC 2H 5(C 2H 5SH) 3 are produced by our experiment. From n≥5, the cluster ion of Al +(C 2H 5SH) n becomes more and more predominant.