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，已经报道了许多成功的例子来观察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，短周期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。到目前为止，实验和理论都集中在小的双原子分子上，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，我们的目标是通过实验和理论相结合的方法来研究脉冲与更复杂分子的定制场的相互作用。具体来说，我们想要跟踪和控制中性状态下的诱导动力学，在中性状态下，化学反应主要发生。所选择的系统，如核碱基尿嘧啶或质子转移系统3-氨基丙烯醛，提供各种核和电子自由度，我们的目标是通过以相位作为突出控制旋钮来定制电场波形来同时控制。为了进行实验，我们的目标是紫外激发，它共振地填充激发态。延时控制脉冲，具有定制的场偶电子和/或核自由度，用于指导分子过程的演变。通过库仑爆炸或光电子能谱，将使用极紫外的第三个脉冲来监测控制。进行理论研究是为了分析和理解潜在的过程，并为实验参数提供指导。为此，我们将扩展我们自己设计的程序代码，同时从双原子到多原子系统处理核和电子运动的量子动力学。这将使我们能够探索核-以及电子波包的相位控制，并制定策略，使控制最有效。实验和理论结合的结果将导致对复杂分子中的核和电子动力学的详细理解，电子相干的自然寿命以及通过相位控制来引导反应的可能性。

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.