Correlated electron–nuclear motion during non-adiabatic transitions in LiH and its isotopomers
Correlated electron–nuclear motion during non-adiabatic transitions in LiH and its isotopomers
复制标题
LiH及其同位素异构体非绝热跃迁期间的相关电子-核运动
DOI：
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
R. D. Levine
中科院分区：
文献类型：
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作者：
K. Komarova;S. van den Wildenberg;F. Remacle;R. D. Levine
用短的强的几个周期的IR脉冲激发分子触发多个电子态上的相干电子-核动力学。这产生了一种新的初始状态，其中在已经填充的电子状态之间发生非绝热转移。我们探索这一新的功能，使用精确的量子模拟的超快激光诱导解离动力学的LiH-LiD-LiT系列同位素。在这种新型的初始状态之间的耦合电子态的非绝热振幅交换强烈依赖于同位素组成。有效的非绝热耦合强度由两个抵消因素调制。一方面，1/质量因子使得非玻恩-奥本海默耦合对于较重的质量较弱。另一方面，两个非定常核子波包在两个电子态上的动量耦合调制了这种转移。对于较重的同位素，这种耦合的幅度往往更大，并且随着波包动力学的展开而随时间变化。核波包在R-和k-空间中运动的相关性是至关重要的。布居转移的方向随时间的变化，根据在短fs激发期间建立的相干态的演化。此外，较重的同位素异构体通过非绝热相互作用移动较慢，从而允许较长的有效转移持续时间。结果，当波包横穿非绝热耦合区域时，在激发后立即出现的同位素效应迅速增长。我们比较和对比类似的时间相关的质量在N2的非绝热转移的光学可及的单重电子态都是绑定和耦合是非常不同的效果。
Exciting molecules with a short strong few cycle IR pulse triggers coherent electronic–nuclear dynamics on multiple electronic states. This creates a new type of initial state where non-adiabatic transfer takes place between already populated electronic states. We explore this new feature using accurate quantal simulations of the ultrafast laser-induced dissociative dynamics in LiH-LiD-LiT series of isotopomers. In this novel type of initial state the non-adiabatic amplitude exchange between the coupled electronic states strongly depends on isotopic composition. The effective non-adiabatic coupling strength is modulated by two counteracting factors. On one hand, the 1/mass factor makes the non-Born–Oppenheimer coupling weaker for the heavier masses. On the other hand, the transfer is modulated by the momentum coupling of the two non-stationary nuclear wave packets on the two electronic states. The magnitude of this coupling tends to be larger for the heavier isotopes and varies in time as the wave packet dynamics unfold. The correlation in motion of the nuclear wave packets in R- and k-space is then critical. The direction of population transfer changes in time according to the evolution of the coherences built during the short fs excitation. In addition, heavier isotopomers move slower through the non-adiabatic interaction allowing a longer effective duration for the transfer. As a result, an initially very moderate isotope effect in the immediate post excitation population rapidly grows when the wave packets transverse the non-adiabatic coupling region. We compare and contrast with similar time dependent effect of the mass in the non-adiabatic transfer in N2 where the optically accessible singlet electronic states are all bound and the couplings are quite different.
DOI：
10.1063/1.4938423
发表时间：
2016
期刊：
The Journal of chemical physics
影响因子：
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作者：
Guorong Wu;S. Neville;O. Schalk;T. Sekikawa;M. Ashfold;G. Worth;A. Stolow
通讯作者：
Guorong Wu;S. Neville;O. Schalk;T. Sekikawa;M. Ashfold;G. Worth;A. Stolow