Attosecond control and tracing of wavepacket dynamics in excited states in polyatomic molecules

分子过程是由原子核和电子运动驱动的。在过去的几十年里，人们报道了许多成功的例子来观测和控制越来越复杂的分子系统的核自由度。在过去的几年里，几个周期的脉冲和调整其波形的可能性为观察和控制电子的快速运动铺平了道路。迄今为止，实验和理论都集中在小的双原子分子上，并且由于光场（强激光场）的性质，它们在离子状态下的动力学。在我们的建议中，我们的目标是调查，在实验和理论相结合的方法，脉冲与定制的领域与更复杂的分子的相互作用。具体来说，我们希望跟踪和控制中性状态下的诱导动力学，化学反应主要发生在中性状态。所选的系统，如核碱基尿嘧啶或质子转移系统3-氨基丙烯醛，提供了各种核和电子的自由度，我们的目标是通过调整电场波形与相位作为突出的控制旋钮同时控制。为了进行实验，我们的目标是紫外激发，共振填充激发态。具有定制场的时间延迟控制脉冲耦合电子和/或核自由度，用于操纵分子过程的演变。 通过库仑爆炸或光电子能谱法，使用极紫外线中的第三个脉冲监测对照品。理论研究是为了分析和理解潜在的过程，并给出实验参数的指导。在这方面，我们将扩大我们自己设计的程序代码，同时处理原子核和电子运动的量子动力学从量子力学到多原子系统。这将使我们能够探索对原子核和电子波包的相位控制，并制定策略，使控制最有效。实验和理论的结果将导致对复杂分子中的原子核和电子动力学的详细了解，电子相干的自然寿命以及通过相位控制操纵反应的可能性。

Molecular processes are driven by nuclear and electronic motion. Many successful examples to observe and control the nuclear degrees of freedom for molecular systems with increasing complexity have been reported over the last decades. In the past few years few-cycle pulses and the possibility to tailor their waveform paved the way to observe and control even the fast motion of electrons. Experiments as well as theory so far concentrated on small diatomic molecules and due to the nature of the light fields (strong laser fields) on their dynamics in ionic states. In our proposal, we aim at investigating, in a combined experimental and theoretical approach, the interaction of pulses with tailored fields with more complex molecules. Specifically, we want to follow and control the induced dynamics in the neutral states, where chemistry takes place mostly. The selected systems, like the nucleobases uracil or the proton-transfer system 3-aminoacrolein, offer a variety of nuclear and electronic degrees of freedom, which we aim to control simultaneously by tailoring the electric-field waveform with the phase as the prominent control knob. In order to carry out the experiments we aim for an UV excitation, that resonantly populates the excited states . A time-delayed control pulse with tailored field couples electronic and/or nuclear degrees of freedom for steering the evolution of the molecular processes. The control will be monitored, using a third pulse in the extreme ultraviolet, via Coulomb explosion or photoelectron spectroscopy. The theoretical investigations are performed to analyze and understand the underlying processes and to give guidance for the experimental parameters. To this extend we will expand our own designed program code that treats the quantum dynamics of nuclear and electron motion simultaneously from diatomics to polyatomic systems. This will allow us to explore the phase control on the nuclear- as well as on the electronic wavepacket and to develop strategies to make the control most efficient.The results from experiment and theory together will lead to a detailed understanding of the nuclear and electron dynamics in complex molecules, the natural lifetime of electronic coherence and possibilities to steer reactions via phase control.