Effect of laser pulse width on ionization efficiency in supersonic beam-multiphoton ionization-mass spectrometry.
Effect of laser pulse width on ionization efficiency in supersonic beam-multiphoton ionization-mass spectrometry.
复制标题
激光脉冲宽度对超声束-多光子电离-质谱中电离效率的影响。
DOI：
10.1021/ac981315o
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发表时间：
1999
影响因子：
7.4
通讯作者：
T. Imasaka
中科院分区：
文献类型：
--
作者：
Junichi Matsumoto and;T. Imasaka
基于速率方程的动力学模型，计算了不同寿命分子的多光子电离效率。结果强烈地依赖于共振电离的类型，即通过拥挤中间能级的电离或通过离散中间能级的电离。在前一种情况下，为了有效的电离，总是首选比寿命短的激光脉冲。在后一种情况下，10ps的激光脉冲为寿命超过10ps的分子提供了最大的电离效率。对于寿命短于10ps的分子，建议使用脉冲宽度调整为与寿命相同的激光。由计算机模拟得到的结果与一卤代苯的实验数据符合得很好。
The efficiency in multiphoton ionization is calculated for various molecules with different lifetimes, based on a kinetic model using rate equations. The results are strongly dependent on the types of resonance ionization, i.e., ionization through congested intermediate levels or ionization through a discrete intermediate level. In the former case, a laser pulse shorter than the lifetime is always preferred for efficient ionization. In the latter case, a 10-ps laser pulse provides the maximum ionization efficiency for a molecule with a lifetime in excess of 10 ps. For a molecule having a lifetime shorter than 10 ps, the use of a laser whose pulse width is adjusted to the same value as the lifetime is suggested. The results obtained by a computer simulation are in reasonably good agreement with the experimental data obtained for monohalogenated benzenes.