Molecular dynamics model of ultraviolet matrix-assisted laser desorption/ionization including ionization processes.
Molecular dynamics model of ultraviolet matrix-assisted laser desorption/ionization including ionization processes.
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紫外基质辅助激光解吸/电离（包括电离过程）的分子动力学模型。
DOI：
10.1021/jp052945e
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
L. Zhigilei
中科院分区：
文献类型：
--
作者：
R. Knochenmuss;L. Zhigilei
提出了一个包含电离过程的UV-MALDI分子动力学模型。除了前面描述的用于模拟分子体系的激光烧蚀/脱附的呼吸球方法外，它还包括辐射和非辐射衰变、激子跳跃、两个汇集过程和电子捕获。结果证实了Knochenmuss，anal连续统模型的主要结论。化学。2003、75、2199，但更详细地描述了在关键的早期时间区域中烧蚀/解吸和电离过程之间的相互作用。解吸和烧蚀都产生了游离离子，产率与实验相符。第一批分子离子在中性脱附开始前不久以高速发射，这是因为电子从样品顶部逃逸导致的表面电荷。后来的离子在中性分子和团簇的羽流中夹带和加热。星系团被发现在纳秒时间尺度上是稳定的，因此其中的离子即使释放，也只会很慢。激子跳跃率和离子复合平均半径是影响净离子产额的关键参数。
A molecular dynamics model of UV-MALDI including ionization processes is presented. In addition to the previously described breathing sphere approach developed for simulation of laser ablation/desorption of molecular systems, it includes radiative and nonradiative decay, exciton hopping, two pooling processes, and electron capture. The results confirm the main conclusions of the continuum model of Knochenmuss, Anal. Chem. 2003, 75, 2199, but provide a much more detailed description of the interaction between ablation/desorption and ionization processes in the critical early time regime. Both desorption and ablation regimes generate free ions, and yields are in accordance with experiment. The first molecular ions are emitted at high velocities shortly before neutral desorption begins, because of surface charging caused by electron escape from the top of the sample. Later ions are entrained and thermalized in the plume of neutral molecules and clusters. Clusters are found to be stable on a nanosecond time scale, so the ions in them will be released only slowly, if at all. Exciton hopping rate and the mean radius for ion recombination are shown to be key parameters that can have a significant effect on net ion yield.