van der Waals团簇ArHCl的光电离研究

The Photoionization Investigations of van der Waals Cluster ArHCl

用同步辐射光源和光电离质谱研究了分子束中ArHClvanderWaals（vdW）团簇的光电离过程．测量结果表明，分子束中的ArHCl的浓匠与气源压力近似满足如下关系式：a（ArHCl）％＝179×10-8.首次给出了ArHCl团簇的光电高效率曲线，并测得ArHCl+的出现势为12.52±0.03eV。根据实验测量的HCl和ArHCl的电高能，计算出Ar－HCl+的解高能为022±0.03eV.用Gaussian－94w量化程序计算出解高能约为0.16eV.实验表明当团簇内的Ar电离时，ArHCl+质谱峰强度明显低于预计的强度，是由于体系电离后发生了电荷转移及解离过程．

The photoionization processes of van der Waals (vdW) cluster ArHCl in a molecular beam have been investigated by using synchrotron radiation light source and photoiollization mass spectrometer. The results show that the concentration of the ArHCl dimer is approkimately given by the equation: a(ArHCl)%=1.79×10-8po1.5. The PIE curve of ArHCl has been given for the first time. The appearance potential of ArHCl+ is deterntined to be 12.52±0.03eV. Using the IP values of HCl obtained in our experiment, the bond dissociation energy of ArHCl+ is deduced to be 0.22±0.03eV. The theoretical calculations using Gaussian-94w indicate that the value is about 0.16eV. When Ar in the cluster is ionized, the intensity of ArHCl+ is obviously lower than that expected. It indicates that the charge transfer and dissociation processes have taken place in the system.