Max-Planck Institute of Quantum Optics, Garching, Germany.
Phys Rev Lett. 2012 Feb 10;108(6):063002. doi: 10.1103/PhysRevLett.108.063002. Epub 2012 Feb 8.
The steering of electron motion in molecules is accessible with waveform-controlled few-cycle laser light and may control the outcome of light-induced chemical reactions. An optical cycle of light, however, is much shorter than the duration of the fastest dissociation reactions, severely limiting the degree of control that can be achieved. To overcome this limitation, we extended the control metrology to the midinfrared studying the prototypical dissociative ionization of D(2) at 2.1 μm. Pronounced subcycle control of the directional D(+) ion emission from the fragmentation of D(2)(+) is observed, demonstrating unprecedented charge-directed reactivity. Two reaction pathways, showing directional ion emission, could be observed and controlled simultaneously for the first time. Quantum-dynamical calculations elucidate the dissociation channels, their observed phase relation, and the control mechanisms.
利用波形控制的少周期激光可以控制分子中电子运动的方向，从而可能控制光诱导化学反应的结果。然而，一个光周期比最快的离解反应的持续时间要短得多，这严重限制了可以实现的控制程度。为了克服这一限制，我们将控制计量学扩展到中红外区域，研究了 2.1μm 处 D(2)的典型离解电离。从 D(2)(+)的碎裂中观察到 D(+)离子发射的明显亚周期控制，这证明了前所未有的电荷导向反应性。首次可以同时观察和控制表现出定向离子发射的两种反应途径。量子动力学计算阐明了离解通道、它们的观察到的相位关系和控制机制。
