355nm激光作用下CH_3I分子的多光子电离解离  

Multiphoton ionization and dissociation of CH_3I at 355 nm

作　　者：李丽[1] 孔祥和[1] 张树东[1] 刘存海[1] 孙志青[1] 刘建苹[1] 张良芳[1] 乔光[1] 

机构地区：[1]曲阜师范大学物理系,山东曲阜273165

出　　处：《量子电子学报》2007年第4期443-446,共4页Chinese Journal of Quantum Electronics

摘　　要：利用飞行时间质谱仪在超声射流冷却条件下研究了CH_3I分子在355nm激光作用下的多光子电离解离机制。得到了分子的飞行时间质谱,质谱中有较强的H^+、CH_3^+和I^+信号,较弱的C^+,CH^+、CH_2^+和母体离子CH_3I^+信号,CH_3I^+的出现表明CH_3I分子的多光子电离解离(MPID)属母体离子阶梯模式:CH_3I分子由双光子共振激发到里德堡C态,处于该激发态的母体分子继续吸收光子上泵浦至电离态形成母体离子CH_3I^+,碎片离子可由母体离子解离形成。同时结合母体离子及碎片离子的出现势对CH_3I分子的多光子电离解离通道进行分析,提出了可能的解离电离通道。The mechanisms of multiphoton ionization （MPI） and dissociation of CH3I at 355 nm are studied under supersonic beam conditions with time-of-flight mass spectrometer. MPI mass spectrum consists mostly of fragment ions, H^＋, CH^＋ and I^＋. In addition, weak signals of C^＋, CH^＋, CH^＋, and CH3I^＋ are also observed in the spectrum. This is consistent with the parent-ion ladder mechanism in which the parent molecules are two-photon resonantly excited to Rydberg C state and then ionized through an additional one-photon absorption to form CH3I^＋. Fragment ions are produced by dissociating CH3I^＋. According to the appearance potential of the parent and fragment ions, the main possible channels of the MPI and photodissociation of CH3I are analyzed.

关 键 词：光谱学 多光子电离解离 碘甲烷 飞行时间质谱 

分 类 号：O561.4[理学—原子与分子物理]