首页> 外文期刊>Journal of mass spectrometry: JMS >Molecular dynamics simulations of MALDI: laser fluence and pulse width dependence of plume characteristics and consequences for matrix and analyte ionization
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Molecular dynamics simulations of MALDI: laser fluence and pulse width dependence of plume characteristics and consequences for matrix and analyte ionization

机译:MALDI的分子动力学模拟:羽流特性的激光能量密度和脉冲宽度依赖性以及基质和分析物电离的后果

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Molecular dynamics simulations of matrix-assisted laser desorption/ionization were carried out to investigate laser pulse width and fluence effects on primary and secondary ionization process. At the same fluence, short (35 or 350 ps) pulses lead to much higher initial pressures and ion concentrations than longer ones (3 ns), but these differences do not persist because the system relaxes toward local thermal equilibrium on a nanosecond timescale. Higher fluences accentuate the initial disparities, but downstream differences are not substantial. Axial velocities of ions and neutrals are found to span a wide range, and be fluence dependent. Total ion yield is only weakly dependent on pulse width, and consistent with experimental estimates. Secondary reactions of matrix cations with analyte neutrals are efficient even though analyte ions are ablated in clusters of matrix.
机译:进行了分子辅助激光解吸/电离的分子动力学模拟,以研究激光脉冲宽度和注量对一次和二次电离过程的影响。在相同的通量下,短脉冲(35或350 ps)导致的初始压力和离子浓度比较长脉冲(3 ns)高得多,但这些差异不会持续存在,因为系统在纳秒级的时间尺度上趋向局部热平衡。较高的注量会加剧初始差异,但下游差异并不明显。发现离子和中性的轴速度跨越很宽的范围,并且取决于注量。总离子产量仅微弱地取决于脉冲宽度,并且与实验估计值一致。即使分析物离子在基质簇中被烧蚀,基质阳离子与分析物中性物的二次反应也是有效的。

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