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

以极短激光脉冲的形式提供强大且精确控制的电场。这些场被用来从字面上观察电子如何在原子和分子中运动，并通过这种脉冲控制电子结构的转变。电子和光子作为这些过程的信使，通过它们的能量分布和发射角度到达我们。对这种分布的精确解释以及理论和计算验证是本项目的总体目的。我们的主要指导方针是建立明确的理论数据，这样做的一组原子和分子系统，被广泛用于强脉冲实验。这些系统包括（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，只有两个原子组成的分子（双原子），最后是没有对称性或对称性大大降低的较大分子。在我们的计算中，只有电子动力学将被调查，占主导地位的过程高达约1飞秒的时间尺度。该项目的初始阶段完全基于近年来建立的我们小组的数学和计算发展，这是第一次允许用可管理的计算机资源精确计算这种现象。为了在这一方向上取得进一步进展，方法开发约占本项目研究时间的25%。我们的数据将被用来回答这样的问题：是什么原因导致观察到的电子发射时间延迟？(Not即使对于最简单的惰性气体氦原子也能完全解释）。我们能想象电子脱离是一个只涉及单个电子的过程吗？还是电子的集体运动决定了发射光谱？这个问题的答案预计取决于分子种类。发出的光告诉我们分子的内部结构是什么？我们只看到电子的表皮（价电子），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?