State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
Laboratoire de chimie théorique, Département de Chimie, Université de Sherbrooke, Sherbrooke, Quebéc J1K 2R1, Canada.
Phys Rev Lett. 2014 Nov 7;113(19):193901. doi: 10.1103/PhysRevLett.113.193901.
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 Schrödinger 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.
采用全维含时薛定谔方程的数值模拟方法，研究了非玻恩-奥本海默处理下的 H(2)(+)、D(2)(+)中的分子高阶谐波产生（MHOHG）。与以往关于 MHOHG 中腔内动力学幅度调制的研究相反，我们在 MHOHG 中演示了频率调制（FM）的循环间动力学。核运动通过强激光脉冲诱导 FM。与固定核近似相比，由于增强的电离与核间距离有关，MHOHG 的强度要高得多。MHOHG 中每个谐波的光谱的宽度和对称性编码了关于分子在激光脉冲上升和下降部分的解离过程的丰富信息，这些信息可用于检索核动力学。研究了同位素效应以确认 FM 机制。
