BrCl紫外光电子能谱实验及理论研究

Photoelectron Spectroscopy (PES) and Theoretical Studies on Bromine Monochloride

采用紫外光电子能谱研究了影响大气臭氧浓度的重要卤素互化物一氯化溴的精细电离能谱 .实验得到BrCl的第一绝热电离能和垂直电离能分别为 10 95eV和 11 0 0eV .BrCl的最高占据轨道 6π电离产生了明显的旋轨分裂谱带 .这对旋轨分裂谱带分别清晰地显示出 4个振动精细结构峰 .频率分析显示BrCl分子最高占据轨道为弱反键性质 .比较了HF方法和外壳层格林函数方法 (OVGF)对电离能的计算结果 ,并对实验值进行了分析比较及指认 .采用实验构型OVGF方法给出的电离能结果无论在低电离能区还是在高电离能区都和实验值一致 ,特别是第一垂直电离能 10 988eV与实验值 11 0

Bromine monochloride has been thought to play an important role in surface ozone depletion at polar sunrise recently. The photoelectron spectroscopy (PES) of BrCl is reported. Research shows that the first adiabatic and vertical ionization potential of bromine monochloride are 10.95 eV and 11 00 eV, respectively. The removal of an electron from the highest occupied orbital (HOMO) of bromine monochloride leads to obvious spin orbit coupling peaks which exhibit fine vibrational structure. The analysis of vibrational frequencies shows that the HOMO has a slightly antibonding character. Comparison of different calculations indicates that the Outer Valence Green's Function (OVGF) method gives extremely good results in the calculation of ionization potential, which is in excellent accordance with the experimental values, especially the first vertical ionization potential (10 988 eV).