Collision-induced few-body dynamics of atomic and molecular systems

碰撞引起的原子和分子系统的少体动力学

• 批准号: RGPIN-2014-03611
• 负责人: Kirchner, Tom
• 金额: $ 2.26万
• 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: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=587310
• 关键词: Collision; induced; few; body; dynamics

Atoms and molecules are objects of the quantum world. Given that the basic laws of quantum mechanics have been known since the 1920s, one might think that atomic and molecular structure and dynamics are well understood by now and can be calculated, using those laws, to any desired level of accuracy. This is not the case. When it comes to dynamics, exact solutions of the known equations are not feasible, except for the simplest situations, and they will not be feasible for some time to come despite the ever-increasing availability of computational resources. At the heart of the matter lies the complexity of the quantum-mechanical few-body problem, and on a fundamental level, it is the interest in this problem that drives this research program. We will study quantal few-body dynamics by looking into collisions of ions with atoms and molecules and solving simplified versions of the fundamental equations that govern the collisional interactions. These simplified equations are still far to complex to be solved in pen and paper form. Accordingly, we will develop algorithms and computer programs to obtain numerical solutions. Comparing them with experimental data will shed light on the quantum dynamics at play and on the usefulness and the limitations of our methods, thereby advancing our understanding of the quantum-mechanical few-body problem. Our studies will also benefit the experimentalists working in this area. They will assist them in interpreting their data and guide them in the design of future experiments. For example, recent ionization measurements of lithium atoms have raised the question whether certain processes which involve two of the three lithium electrons contribute to the measured spectra. We plan to study the role and the nature of these processes. One question our calculations will address is whether they are dominated by independent interactions of the impinging ion with each electron, or if the interaction between the electrons is important as well. The latter interaction is associated with so-called electron-correlation effects, which play a central role in many atomic, molecular and condensed-matter systems and give rise to such interesting phenomena as superconductivity. Our work will also have significant applications. A major goal of this research program is to push our methods to make them applicable to collisions involving organic molecules. This will be relevant for the field of radiobiology. When biological tissue is irradiated by protons or heavy ions, electrons are set free and the ionized molecules may break apart. In tumour radiation therapy this contributes to the desired destruction of the tumour and to the undesired destruction of the surrounding tissue. Understanding the problem of radiation damage on a fundamental level requires the detailed analysis of the underlying collision processes. This is what our research is concerned with. In the long term it will benefit the complex field of damage to large molecules such as DNA bases and will potentially have some societal impact in that its outcomes may contribute to a more successful treatment of cancer.

原子和分子是量子世界的对象。鉴于自1920年代以来就已经知道了量子力学的基本定律，因此人们可能会认为原子和分子结构和动力学现在已经充分理解，并且可以使用这些定律以任何所需的准确性来计算。事实并非如此。当涉及动态时，除了最简单的情况外，已知方程的精确解决方案是不可行的，尽管计算资源的可用性不断增加，但它们在一段时间内将是不可行的。这件事的核心是量子力学几个身体问题的复杂性，在基本层面上，对这个问题的兴趣驱动了这项研究计划。 我们将通过研究与原子和分子的碰撞以及求解控制碰撞相互作用的基本方程的简化版本来研究数量的几体动力学。这些简化的方程仍然很复杂，可以以笔和纸张形式解决。因此，我们将开发算法和计算机程序以获取数值解决方案。将它们与实验数据进行比较，将阐明游戏中的量子动力学以及我们方法的有用性和局限性，从而促进我们对量子力学几个身体问题的理解。我们的研究还将受益于在这一领域工作的实验者。他们将协助他们解释数据，并指导他们未来的实验设计。例如，锂原子的最新电离测量结果提出了一个问题，该问题是否涉及三个锂电子中的两个过程是否有助于测得的光谱。我们计划研究这些过程的作用和性质。我们的计算将解决的一个问题是，它们是否是由撞击离子与每个电子的独立相互作用所占据的，还是电子之间的相互作用也很重要。后一种相互作用与所谓的电子相关效应有关，这些效应在许多原子，分子和凝结的系统中起着核心作用，并引起了像超导性等有趣现象。 我们的工作也将有重要的应用。该研究计划的一个主要目标是推动我们的方法使其适用于涉及有机分子的碰撞。这将与放射生物学领域有关。当生物组织被质子或重离子照射时，将电子设置为游离，并且电离分子可能会破裂。在肿瘤辐射疗法中，这有助于肿瘤的所需破坏以及周围组织的不期望破坏。了解基本水平上的辐射损伤问题需要对基础碰撞过程进行详细分析。这就是我们的研究所关注的。从长远来看，它将受益于大分子（例如DNA碱基）的复杂损害领域，并有可能产生一些社会影响，因为其结果可能有助于更成功地治疗癌症。