Charge-directed reactivity of molecules and its control by short laser pulses

将分子暴露在超短激光脉冲中可以触发激发或电离系统中的纯电子动力学。在电离的情况下，这些动力学可能表现为在整个系统中最初产生的空穴电荷的超快迁移，并被称为电荷迁移。由于电子运动和核运动之间的耦合，对纯电子动力学的控制提供了极有趣的可能性，通过在很早的阶段预先确定反应结果来指导后续的化学反应。这就是为什么电荷迁移现象越来越受到科学界的关注，目前有几个小组正在准备利用新型阿秒脉冲技术研究这一过程的实验。在这个项目的第一阶段，我们开发了方案和协议，允许设计超短激光脉冲，可以有效地控制多原子分子中的电子电荷迁移过程。更新项目的主要目标是开发一种方法，允许纯量子力学地处理中等大小分子阳离子在激光场存在下的耦合电子-核动力学，并将这种方法应用于实验有趣的系统。这将回答原子化学的关键问题，即我们能否通过操纵纯电子电荷迁移步骤来控制分子阳离子中的化学反应。这样的计算一方面将为实验学家提供必要的概念理解和解释实验结果的帮助，另一方面，将通过提出有趣的系统和要测量的效应来指导未来的实验工作。

Exposing molecules to ultrashort laser pulses can trigger pure electron dynamics in the excited or ionized system. In the case of ionization, these dynamics may manifest as an ultrafast migration of the initially created hole-charge throughout the system and were termed charge migration. Due to the coupling between the electronic and the nuclear motion, the control over the pure electron dynamics offers the extremely interesting possibility to steer the succeeding chemical reactivity by predetermining the reaction outcome at a very early stage.That is why, the charge-migration phenomenon increasingly attracts the attention of the scientific community and at present several groups are preparing experiments to study the process using novel attosecond pulse techniques. In the first period of this project we developed schemes and protocols that allow to design ultrashort laser pulses that can efficiently control the electronic charge migration process in polyatomic molecules.The main goal of the renewal project is to develop methodologies allowing to treat purely quantum mechanically the coupled electron-nuclear dynamics of moderate size molecular cations in the presence of a laser field and to apply this methodology to experimentally interesting systems.This will allow to answer the key question of attochemistry, namely can we steer chemical reactions in molecular cations by manipulating the pure electronic charge-migration step. Such calculations will, on onehand, provide the experimentalists the needed conceptual understanding and help in interpreting the experimental results, and,on the other hand, will guide future experimental efforts by proposing interesting systems and effects to be measured.