We investigate the fragmentation and isomerization of toluene molecules induced by strong-field ionization with a femtosecond near-infrared laser pulse. Momentum-resolved coincidence time-of-flight ion mass spectrometry is used to determine the relative yield of different ionic products and fragmentation channels as a function of laser intensity. Ultrafast electron diffraction is used to capture the structure of the ions formed on a picosecond time scale by comparing the diffraction signal with theoretical predictions. Through the combination of the two measurements and theory, we are able to determine the main fragmentation channels and to distinguish between ions with identical mass but different structures. In addition, our diffraction measurements show that the independent atom model, which is widely used to analyze electron diffraction patterns, is not a good approximation for diffraction from ions. We show that the diffraction data is in very good agreement with ab initio scattering calculations.

中文翻译：

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飞秒飞秒电子衍射和质谱法探测强磁场诱导的甲苯裂解和异构化

我们调查飞秒近红外激光脉冲强场电离诱导的甲苯分子的碎片化和异构化。动量分辨重合飞行时间离子质谱仪用于确定不同离子产物和碎片化通道的相对产率与激光强度的关系。通过将衍射信号与理论预测值进行比较，可以使用超快电子衍射来捕获在皮秒级刻度上形成的离子的结构。通过两次测量和理论的结合，我们能够确定主要的碎裂通道并区分质量相同但结构不同的离子。此外，我们的衍射测量结果表明，独立原子模型 广泛用于分析电子衍射图的离子不能很好地近似于离子衍射。我们表明衍射数据与从头算起散射计算。