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.

本项目关注的是对最近发展的“非绝热跳跃量子分子动力学”（NA-QMD-H）方法的扩展，明确地将外部激光场包括在谐波任意长脉冲分子动力学的理论描述中。新方法允许全维（包括旋转、振动和电子激发）同时从头开始描述激光驱动的双原子分子解离和电离，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完全依赖于时间的Schrödinger方程的近似解。这是Dresden的NA-QMD方法多年发展的最终目标（参见“Eigene Vorarbeiten”一节）。这一目标将通过对原子核的近似量子力学处理来实现，其中经典轨迹在量子力学决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，Floquet曲面（在脉冲期间）和Born-Oppenheimer曲面（用于脉冲后的松弛动力学）将被应用。结合量子力学决定的单个表面之间的跃迁速率（“跳跃”），这应该允许对激光驱动的分子动力学包括电子-核相关的准确描述。对于H2+，我们已经有了这种方法的经验。将该方法扩展到双原子多电子分子是本项目较窄的关注范围。第一次，密度-泛函-理论- Kohn-Sham系统的floquet表面对应于这里的分子应使用。该方法的另一个新的和重要的点是通过在中性、单个或多个电离分子的表面之间跳跃来描述光电离，这样就可以对所有（相关）电离通道进行完整的描述。该项目已与海德堡马克斯-普朗克研究所<s:1>克物理研究所（MPIK）达成合作协议（见附件）。在MPIK，运动学完整的实验有关解离和电离是用反应显微镜进行的。在与MPIK协商后，首先要对氩二聚体进行具体的计算（之后还要对其他惰性气体以及O2和N2进行计算），结果要与实验结果进行比较，并帮助解释。此外，还计划对泵浦探测实验的解释进行模拟。新方法允许在计算中明确包含泵浦和探针脉冲。一个共同的目标，除其他外，是研究分子动力学可以在多大程度上通过适当选择激光参数来操纵。