Electronic structure and dynamics in strong fields: precision spectra for multi-electron systems

强而精确控制的电场以极短的激光脉冲的形式存在。这些场被用来观察电子如何在原子和分子中运动，并通过这些脉冲控制电子结构的转变。电子和光子通过它们在能量和发射角度上的分布，作为这些过程的信使到达我们这里。这种分布的精确解释和理论和计算验证是本项目的总体目的。我们的主要方针是建立明确的理论数据，并为一组广泛用于强脉冲实验的原子和分子系统这样做。系统包括（越来越复杂的）氦原子和氢分子，较重的稀有气体原子Ne， Ar等，仅由两个原子组成的分子（双原子），最后是没有或强烈减少对称性的大分子。在我们的计算中，只研究电子动力学，它在大约1飞秒的时间尺度上主导着过程。该项目的初始阶段完全基于我们小组近年来建立的数学和计算发展，这是第一次允许使用可管理的计算机资源对这种现象进行精确计算。为了在这个方向上取得进一步的进展，在这个项目中，方法开发大约占研究时间的25%。我们的数据将被用来回答这样的问题：是什么导致了电子发射中观察到的时间延迟？（即使是最简单的惰性气体氦原子也不能完全解释）。我们能把电子分离想象成只涉及一个电子的过程吗？还是电子的集体运动决定了发射光谱？这个问题的答案取决于分子种类。发射的光告诉我们分子的内部结构是什么？我们只看到电子外壳（价电子）吗，我们看到核心了吗，我们看到电子的运动了吗？

Strong and precisely controlled electric fields are available in the form of extremely short laser pulses. These fields are used to literally observe how electrons move in atoms and molecules and to control the transformation of electronic structure by such pulses. Electrons and photons reach us as the messengers of these processes by their distribution in energy and emission angles. The precise interpretation and theoretical and computational verification of such distributions is the overall purpose of this project. Our principal guideline is to establish unambiguous theoretical data, and to do so for a set of atomic and molecular systems that are widely used in experiments with strong pulses. The systems include (in increasing complexity) the Helium atom and the Hydrogen molecule, heavier noble gas atoms Ne, Ar, etc., molecules consisting of only two atoms (diatomics), and finally larger molecules with no or strongly reduced symmetry. In our computations, only the electronic dynamics will be investigated, which dominates the processes up to time-scales of about 1 femtosecond. The initial stage of the project is entirely based on mathematical and computational developments by our group that were established during recent years an that, for the first time, allow the precise calculation of such phenomena with manageable computer resources. To progress further in this direction, method development constitutes about 25% of the research time in this project. Our data will be used to answer questions like: what causes the observed time-delays in the emission of electrons? (Not fully explained even for the simplest noble gas atom of Helium). Can we imagine electron detachment as a process involving only a single electron, or does the collective motion of electrons determine emission spectra? The answer to this question is expected to depend on the molecular species. What does the emitted light tell us about the internal structure of the molecule? Do we only see the electronic skin (valence electrons), do we see the core, do we see motion of electrons?