Nikodem Astrid, Levine R D, Remacle F
Département de Chimie, B6c, Université de Liège , B4000 Liège, Belgium.
The Fritz Haber Center for Molecular Dynamics and Institute of Chemistry, The Hebrew University of Jerusalem , Jerusalem 91904, Israel.
J Phys Chem A. 2016 May 19;120(19):3343-52. doi: 10.1021/acs.jpca.6b00140. Epub 2016 Mar 9.
The quantum wave packet dynamics following a coherent electronic excitation of LiH by an ultrashort, polarized, strong one-cycle infrared optical pulse is computed on several electronic states using a grid method. The coupling to the strong field of the pump and the probe pulses is included in the Hamiltonian used to solve the time-dependent Schrodinger equation. The polarization of the pump pulse allows us to control the localization in time and in space of the nonequilibrium coherent electronic motion and the subsequent nuclear dynamics. We show that transient absorption, resulting from the interaction of the total molecular dipole with the electric fields of the pump and the probe, is a very versatile probe of the different time scales of the vibronic dynamics. It allows probing both the ultrashort, femtosecond time scale of the electronic coherences as well as the longer dozens of femtoseconds time scales of the nuclear motion on the excited electronic states. The ultrafast beatings of the electronic coherences in space and in time are shown to be modulated by the different periods of the nuclear motion.
利用网格方法，在几个电子态上计算了超短、极化、强单周期红外光脉冲对LiH进行相干电子激发后的量子波包动力学。用于求解含时薛定谔方程的哈密顿量中包含了与泵浦脉冲和探测脉冲强场的耦合。泵浦脉冲的极化使我们能够控制非平衡相干电子运动以及随后核动力学在时间和空间上的局域化。我们表明，由总分子偶极矩与泵浦和探测电场相互作用产生的瞬态吸收，是振动电子动力学不同时间尺度的一种非常通用的探测手段。它既能探测电子相干的超短飞秒时间尺度，也能探测激发电子态上核运动的长达几十飞秒的时间尺度。电子相干在空间和时间上的超快拍频被证明受到核运动不同周期的调制。
