Attosecond Nuclear Dynamics in the Ammonia Cation: Relation between High-Harmonic and Photoelectron Spectroscopies
Attosecond Nuclear Dynamics in the Ammonia Cation: Relation between High-Harmonic and Photoelectron Spectroscopies
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DOI：
10.1002/cphc.201201022
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发表时间：
2013-05-10
期刊：
影响因子：
2.9
通讯作者：
Woerner, Hans Jakob
中科院分区：
文献类型：
--
作者：
Kraus, Peter Michael;Woerner, Hans Jakob
我们报道了在阿秒时间尺度上测量氨阳离子中的伞运动。该运动是由强场电离制备的，并通过高次谐波产生过程的光复合来探测。在多个波长(0.8、1.44、1.8米)进行这种测量使我们能够在广泛的时间范围(0.83.8飞秒)上跟踪核动态。通过强场电离率的振动态依赖关系，发现驱动场的强度对观测到的动力学有很大的影响。我们推导了一个包含这些效应的一般模型，并在高次谐波光谱和经典光电子光谱之间建立了一种新的联系。我们的模型再现了观察到的动力学及其对驱动场强度的依赖关系。此外，该模型在几飞秒的时间尺度上比大多数以前的理论预测了更丰富的核动力学。新预测的特征反映了分子阳离子的量子化振动能级结构。
We report measurements of the umbrella motion in the ammonia cation on the attosecond time scale. The motion is prepared by strong-field ionization and probed by photorecombination through the process of high-harmonic generation. Performing such measurements at multiple wavelengths (0.8, 1.44, 1.8 m) enables us to follow the nuclear dynamics over a broad temporal range (0.83.8 fs). The intensity of the driving field is found to have a significant impact on the observed dynamics through the vibrational-state dependence of the strong-field ionization rates. We derive a general model that includes these effects and establishes a new link between high-harmonic spectroscopy and classical photoelectron spectroscopy. Our model reproduces the observed dynamics and their dependence on the intensity of the driving field. Moreover, the model predicts much richer nuclear dynamics on the few-fs timescale than most previous theories. The newly predicted features are shown to reflect the quantized vibronic level structure of the molecular cation.