Dissociation and ionization of diatomic molecules in laser fields - full dimensional ab-initio description including electron-nuclear correlations

激光场中双原子分子的解离和电离 - 全维从头计算描述，包括电子-核相关性

• 批准号: 280059503
• 负责人: Professor Dr. Rüdiger Schmidt (†)
• 金额: --
• 依托单位: Max-Planck-Institut für Kernphysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/280059503?language=en
• 关键词: Dissociation; ionization; diatomic; molecules; laser

The concern of this project is the extension of the recently developed "Non-Adiabatic Quantum Molecular Dynamics with Hopping" (NA-QMD-H) method to explicitly include an external laser field in the theoretical description during the molecular dynamics in harmonic, arbitrary long pulses. The new approach allows for an full-dimensional (including rotation, vibration, and electronic excitation) simultaneous ab-initio description of the laser-driven dissociation and ionization of two-atomic molecules, including quantum effects in the nuclear dynamics. This approach therefore is an approximative solution of the full time-dependend Schrödinger equation for electrons and nuclei. It is the ultimate goal of many years of development of Dresden's NA-QMD method (see Section "Eigene Vorarbeiten"). This goal shall be achieved with an approximate quantum-mechanical treatment of the nuclei, where classical trajectories are propagated on quantum-mechanically determined energy surfaces. The choice of these surfaces is crucical. In the intended method, Floquet surfaces (during the pulse) and Born-Oppenheimer surfaces (for the relaxation dynamics following the pulse) will be applied. In connection with quantum-mechanically determined transition rates between single surfaces ("hopping"), this should allow for an accurate description of the laser-driven molecular dynamics including electron-nuclear correlations. For H2+, we already have experience with this approach. The challenging extension of the method to two-atomic multi-electron molecules is the narrower concern of the present project. For the first time, density-functional-theory-Floquet surfaces of the Kohn-Sham system corresponding to the molecule shall be used here. A further new and important point of the method is the description of photoionization by hopping between surfaces of the neutral, single, or multiple ionized molecule, such that a complete description of all (relevant) ionization channels should be possible.For this project a cooperation agreement with the Max-Planck-Institut für Kernphysik (MPIK) Heidelberg has been concluded (see attachments). At the MPIK, kinematically complete experiments concerning the dissociation and ionization are performed using a reaction microscope. In consultation with the MPIK, specific calculations shall be done at first for argon dimers (later also for other noble gases as well as O2 and N2), the results shall be compared to the experimental findings and help with their interpretation. Furthermore, simulations for the interpretation of pump-probe experiments are planned. The new method allows for an explicit inclusion of the pump and the probe pulse in the calculation. A common aim, among others, is to investigate to what extent the molecular dynamics can be manipulated by suitable choices of the laser parameters.

该项目关注的是最近开发的“带跳跃的非绝热量子分子动力学”（NA-QMD-H）方法的扩展，以在谐波、任意长脉冲的分子动力学过程中明确地将外部激光场纳入理论描述中。 新方法允许对激光驱动的二原子分子解离和电离进行全维（包括旋转、振动和电子激发）同时从头开始描述，包括核动力学中的量子效应。因此，这种方法是电子和原子核的完全瞬态薛定谔方程的近似解。这是德累斯顿 NA-QMD 方法多年发展的最终目标（参见“Eigene Vorarbeiten”部分）。 这一目标应通过对原子核进行近似量子力学处理来实现，其中经典轨迹在量子力学确定的能量表面上传播。这些表面的选择至关重要。在预期的方法中，将应用 Floquet 曲面（在脉冲期间）和 Born-Oppenheimer 曲面（用于脉冲后的弛豫动力学）。与量子力学确定的单表面之间的跃迁速率（“跳跃”）相关，这应该可以准确描述激光驱动的分子动力学，包括电子-核相关性。对于 H2+，我们已经有这种方法的经验。 该方法对二原子多电子分子的挑战性扩展是本项目的较小关注点。这里首次使用与分子相对应的 Kohn-Sham 系统的密度泛函理论 Floquet 表面。该方法的另一个新的重要点是通过在中性、单个或多个电离分子的表面之间跳跃来描述光电离，从而可以完整地描述所有（相关）电离通道。对于该项目，与海德堡马克斯普朗克核物理研究所（MPIK）达成了合作协议（见附件）。在 MPIK，使用反应显微镜进行有关解离和电离的运动学完整实验。 与MPIK协商后，首先应针对氩二聚体（随后也针对其他惰性气体以及O2和N2）进行具体计算，将结果与实验结果进行比较并帮助其解释。此外，还计划对泵浦探针实验进行模拟解释。新方法允许在计算中明确包含泵浦和探测脉冲。其中一个共同的目标是研究通过适当选择激光参数可以在多大程度上操纵分子动力学。