Strong-field molecular alignment mediated by nonadiabatic charge localization
Strong-field molecular alignment mediated by nonadiabatic charge localization
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DOI：
10.1103/physreva.100.063423
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发表时间：
2019-11
影响因子：
2.9
通讯作者：
D. Romanov;R. Levis
中科院分区：
文献类型：
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作者：
D. Romanov;R. Levis
探索了一种分子旋转自由度与强非共振超短激光脉冲有效相互作用的新模式。较大分子或分子离子中的瞬态非绝热电荷重新分布 (TNCR) 会引起脉冲扭矩相互作用，取代了基于激光场与电子子系统的微扰相互作用的传统分子排列机制，如线性各向异性极化率或超极化率所示。我们在紧密结合双原子分子的流行通用模型上探索了这种新的对齐机制。我们考虑当分子最初处于旋转基态时旋转波包形成的情况。与各向异性极化情况相比，TNCR 相互作用产生的旋转波包由具有更高旋转量子数的态组成，并且脉冲后排列振荡与传统相互作用产生的振荡不同相。当强激光场实际上引起分子的广泛非共振激发和/或电离时，TNCR 相互作用模式预计将发挥主要作用。
A new mode of effective interaction of molecular rotational degrees of freedom with an intense, nonresonant, ultrashort laser pulse is explored. Transient nonadiabatic charge redistribution (TNCR) in larger molecules or molecular ions causes impulsive-torque interaction that replaces the traditional mechanism of molecular alignment based on perturbative interaction of the laser field with electronic subsystem as manifested in linear anisotropic polarizability or hyperpolarizability. We explore this new alignment mechanism on a popular generic model of a tight-binding diatomic molecule. We consider the case of rotational wavepacket formation when a molecule is initially in the ground rotational state. The rotational wavepacket emerging from the TNCR interaction consists of states with higher rotational quantum numbers, in comparison with the anisotropic-polarizability case, and the after-pulse alignment oscillations are out-of-phase with those resulting from the traditional interaction. The TNCR interaction mode is expected to play a major role when a strong laser field actually causes extensive nonresonant excitation and/or ionization of a molecule.