Probing Nuclear Motion by Frequency Modulation of Molecular High-Order Harmonic Generation
Probing Nuclear Motion by Frequency Modulation of Molecular High-Order Harmonic Generation
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DOI：
10.1103/physrevlett.113.193901
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发表时间：
2014-11-07
影响因子：
8.6
通讯作者：
Bandrauk, Andre D.
中科院分区：
文献类型：
--
作者：
Bian, Xue-Bin;Bandrauk, Andre D.
通过对相应的全维含时薛定谔方程的数值模拟，研究了H-2(+)，D-2(+)的非Born-Oppenheimer处理过程中的分子高次谐波产生。与前人对MHOHG周期内动力学的调幅研究不同，我们证明了红移是MHOHG周期内动力学的频率调制。调频是由使用强激光脉冲的原子核运动引起的。与固定核近似相比，由于增强电离依赖于核间距离，MHOHG的强度要高得多。MHOHG中各次谐波光谱的宽度和对称性编码了分子在激光脉冲上升和下降部分的解离过程的丰富信息，可以用来恢复核动力学。研究了同位素效应，以确定FM机理。
Molecular high-order harmonic generation (MHOHG) in a non-Born-Oppenheimer treatment of H-2(+), D-2(+), is investigated by numerical simulations of the corresponding time-dependent Schrodinger equations in full dimensions. As opposed to previous studies on amplitude modulation of intracycle dynamics in MHOHG, we demonstrate redshifts as frequency modulation (FM) of intercycle dynamics in MHOHG. The FM is induced by nuclear motion using intense laser pulses. Compared to fixed-nuclei approximations, the intensity of MHOHG is much higher due to the dependence of enhanced ionization on the internuclear distance. The width and symmetry of the spectrum of each harmonic in MHOHG encode rich information on the dissociation process of molecules at the rising and falling parts of the laser pulses, which can be used to retrieve the nuclear dynamics. Isotope effects are studied to confirm the FM mechanism.