邻溴甲苯多光子电离质谱及从头算

Multiphoton ionization mass spectra of o-bromotoluene and ab initio calculation

在波长为266 nm激光作用下,利用激光质谱法,得到了邻溴甲苯分子的多光子电离飞行时间质谱.通过分析部分碎片离子占总离子信号的分支比对激光强度的依赖关系,得出邻溴甲苯的多光子电离过程主要是母体分子解离—中性碎片电离.母体分子的解离主要有直接解离和先异构后解离两个可能的通道,对C_7H_7^+、C_6H^+、C_5H_5^+等碎片离子的可能形成过程进行了讨论,并利用从头计算法对邻溴甲苯光解过程中的氢原子迁移反应作了理论验证.

The multiphoton ionization time-of-flight mass spectra of o-bromotoluene at 266 nm were obtained using laser mass spectroscopy technique. By analysis of the percentage of part fragment ions to the total ion current and dependence on laser intensity of the molecule,we concluded that the primary MPI process of o-bromotoluene is multiphoton dissociation of parent molecule and multiphoton ionization of neutral fragment. Parent molecule mainly has two possible dissociation channels, one is the direct dissociation,the other is the first isomerism latter dissociation, we discussed some formation process of the fragmentcations,i, e. C7 H^＋ , C6 H^＋ , C5 H5^＋ etc. The hydrogen atom transfer reaction of o-bromotoluene in photolysis process was made the theory confirmation using ab initio calculation.