Collision- and laser-induced few-body dynamics in atomic and molecular systems

原子和分子系统中碰撞和激光诱导的少体动力学

• 批准号: RGPIN-2019-06305
• 负责人: Kirchner, Tom
• 金额: $ 2.04万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=763023
• 关键词: Collision; laser; induced; few; body

When an atom or a molecule is hit by an energetic ion or is exposed to a strong laser field it may release one or several of its electrons. In the case of a molecular target, this process of ionization may be followed by the break-up of the system into neutral and charged fragments which, similarly to the released electrons, may cause further ionization in surrounding matter. These processes are at the heart of the problem of radiation damage of biological tissue. Their quantitative understanding is the principal objective of this research program. Atoms and molecules follow the laws of quantum physics. When they are exposed to strong fields, either through collisional interactions or by laser illumination, the equations derived from those laws to describe their behaviour are so complex that exact solutions are not feasible. Models, advanced theoretical methods and numerical techniques are then required to make predictions on measurement outcomes or to produce numerical data that can be compared with available measurements to help understand the underlying physics and draw conclusions with regard to possible applications. The work described in this proposal is concerned with the development and execution of such models, methods and techniques. Two avenues of research will be pursued. On a fundamental level, we will use atomic collision problems as test beds for the further development of the so-called time-dependent density functional theory (TDDFT) approach, which is one of only a few theoretical methods available for describing collisional and laser-driven many-electron dynamics on a first-principles basis. We will implement a TDDFT scheme on a higher level of approximation than reported before and carry out numerical calculations for ion-atom collisions to help validate and improve the approach. We will also address an outstanding fundamental TDDFT problem related to the calculation of observable quantities. Our work will advance theory and produce data of interest to experimentalists in the field and to researchers in neighbouring disciplines who are, e.g., analyzing X-ray spectra of astrophysical objects or diagnosing high-temperature plasmas in the context of nuclear fusion experiments. On the more applied side we will study ion collisions from biologically relevant molecules, such as DNA/RNA building blocks, by elaborating on a simplified model description which we have proposed recently. Full first-principles calculations are not feasible for these complicated systems, yet reliable theoretical data would be important for an in-depth understanding of the problem of radiation damage of biological tissue. Our research is aimed at filling this void and producing such data. The results of our model calculations will benefit the field of radiobiology and, potentially, have an impact on clinical applications such as tumour therapy with positively-charged ions, thereby contributing to a more successful treatment of cancer.

当原子或分子被能量离子击中或暴露于强激光场时，它可能会释放一个或几个电子。在分子靶标的情况下，这种电离过程可能会破坏系统为中性和带电的片段，与释放的电子相似，这可能会导致周围物质的进一步电离。这些过程是生物组织辐射损伤问题的核心。他们的定量理解是该研究计划的主要目标。 原子和分子遵循量子物理定律。当它们通过碰撞相互作用或激光照明暴露于强场上时，从这些定律中得出的描述其行为的方程式是如此复杂，以至于确切的解决方案是不可行的。然后需要模型，高级理论方法和数值技术来预测测量结果或产生可以与可用测量结果进行比较的数值数据，以帮助了解基本的物理学并就可能的应用得出结论。本提案中描述的工作与此类模型，方法和技术的开发和执行有关。将追求两种研究途径。从基本层面上，我们将使用原子碰撞问题作为测试床，以进一步开发所谓的时间依赖性密度功能理论（TDDFT）方法，这是仅用于描述碰撞和激光驱动和激光驱动的多种理论方法之一。我们将以比以前报道的更高的近似水平实施TDDFT方案，并进行离子原子碰撞的数值计算，以帮助验证和改进方法。我们还将解决与可观察数量的计算有关的杰出基本TDDFT问题。我们的工作将推进理论并为田间的实验者和邻近学科的研究人员提供感兴趣的数据，例如，在核融合实验的背景下，分析天体物理对象的X射线光谱或诊断高温等离子体。在更应用的方面，我们将通过详细阐述我们最近提出的简化模型描述，研究来自生物学相关分子（例如DNA/RNA构建块）的离子碰撞。对于这些复杂的系统，完整的第一原理计算是不可行的，但是可靠的理论数据对于深入了解生物组织的辐射损伤问题至关重要。我们的研究旨在填补这一空白并产生此类数据。我们的模型计算结果将使放射生物学领域受益，并可能对临床应用产生影响，例如肿瘤疗法，并带有带正电荷的离子，从而有助于更成功的癌症治疗。