碘乙烷在532nm激光作用下多光子电离解离机理

MULTIPHOTON IONIZATION MASS SPECTRA OF ETHYL IODIDE AT 532 nm

利用５３２ｎｍ的激光对碘乙烷（Ｃ２Ｈ５Ｉ）分子作了多光子电离解离（ＭＰＩＤ）质谱（ＭＳ）研究。Ｃ２Ｈ５Ｉ分子吸收５３２ｎｍ激光双光子的能量激发跃迁至Ａ带后，碎裂成中性碎片Ｉ原子及Ｃ２Ｈ５自由基，中性碎片再吸收光子经一系列电离解离形成碎片离子。分析了不同激光强度及加速电压下的产物离子与总的碳氢离子强度比值变化，从而更深地揭示了Ｃ２Ｈ５Ｉ分子在５３２ｎｍ激光作用下的ＭＰＩＤ机理。

Multiphoton ionization dissociation(MPID) mass spectra(MS)of ethyl iodide are obtained using a time of flight mass spectrometer at 532 nm, Ethyl iodide is resonantly exited to A band and then dissociates to I atom and C 2H 5 radica1. Fragment ions are produced by ionization and dissociation of neutral fragments, Fragment mechanism is analysed by the discussion of the ratios of product ions to all hydrocarbon ions(not including H + ion) at different laser intensities and accelerating voltages.