266nm激光作用下1，3-二溴苯的多光子电离和解离研究

Study on multiphoton ionization dissociation processes of 1,3-dibromobenzene at 266 nm laser radiation

在波长为266 nm的激光作用下对1,3-二溴苯分子的多光子电离解离过程进行了研究,获得了溴苯分子的MPIF-TOF质谱,并测得了各碎片离子占总离子信号的百分比对激光强度的依赖关系.用这些实验结果分析1,3-二溴苯分子的多光子电离解离机理,得出1,3-二溴苯的MPI过程主要是母体分子解离-中性碎片电离,C_6H_4^+,C_5H_3^+,C_4H_2^+,C_3H^+等碎片离子主要是经过离子离解阶梯模式产生的,并给出了可能的解离通道.

The processes of multiphoton ionization （MPI） dissociation of 1, 3-dibromobenzene was studied at 266 nm. The time of flight mass spectra of 1, 3-dibromobenzene were obtained. We measured the percentage of fragment ions to the total ion current and the dependence on laser intensity of the molecule. Based on the experimental results, the multiphoton ionizationfragmentation （MPIF） mechanism of 1, 3-dibromobenzene was discussed. The conclusion is that the primary channel is multiphoton dissociation of parent molecule and multiphoton ionization of neutral fragment. Some formation channels of the small fragment cations were analyzed, i.e. C6H^＋, C5H3^＋, C4H2^＋, C3H^＋ etc. and most of ion fragments are produced by ion-fragment dissociation staircase.