RUI: The Interaction of Radiation with Free and Confined Quantum Systems

物理系统对入射电磁辐射或带电粒子的响应是自然界最基本的性质之一，对基础科学和应用科学沿着各种技术应用都非常重要。尽管迄今为止对这些过程进行了许多研究，但目前对它们的理解还远远没有完成。这是因为这些过程在可能发生的现象的丰富性方面是多方面的，并且理论极难涵盖所有这些现象，甚至是其中的一些。在这个项目中，自由和受限原子的结构和光谱以及它们与入射电磁辐射或带电粒子的相互作用的理解将得到推进。在该项目中，感兴趣的受限原子被定义为嵌入各种气相富勒烯Cn的中空内部或具有不同高度和宽度的其他类型的可穿透和不可穿透的限制的原子，以及位于平面或非平面石墨纳米结构附近的原子。将揭示光子吸收和入射电子与受限原子和自由原子碰撞的相应过程截面的新趋势。对于自由原子，这将通过考虑混合“纯”空位状态（例如，如Ba中的5s）或“纯”进入粒子状态，在许多原子中具有占主导地位的（将在项目中确定）高阶连续状态激发，首先是Ba和Mn;到目前为止，缺乏所需的理解。 对于受限原子，通过考虑上述不同性质和几何形状的限制所带来的单独和组合效应，通过改变受限原子在限制内的位置，以及通过考虑原子本身的多电子相互作用（电子相关），可以揭示其光谱的新趋势。Hartree-Fock近似、有交换的无规相位近似、多体微扰论方法等，将用于或调整至所述研究。要进行的活动的智力价值是由以下事实决定的：迄今为止，关于不同对称性（球形、非球形、均匀、不均匀、平面、非平面等）的纳米尺度限制的单独和组合效应如何的知识很少。可以改变被限制在其中或位于其附近的原子的结构和光谱。此外，到目前为止，仍然缺乏对原子中纯空位/粒子态与其高阶激发的相互作用的理解。此外，该项目的结果将确定一些最有趣和/或有用的未来测量/计算，可以执行，无论是自由和受限的原子，从而有助于协同该领域的进步。在更广泛的影响范围内，本科生参与和积极参与该项目将加强大学研究和教育的整合。此外，该项目将加强大学的研究基础设施。研究结果将广泛传播给科学界和公众，以提高对科学的认识。社会将受益于通过获得新的基本知识与重要应用的自然现象进行的活动，并通过谁，在他们的职业生涯早期，学生的培训，将获得了进入研究生学习物理或科学和工程职业的独特的专业经验。这些都将对科学和工程的效益、健康、活力和社会的繁荣做出重大贡献。

The response of a physical system to incoming electromagnetic radiation or charged particles is one of the most basic properties of nature of utter importance to both fundamental and applied sciences along with a wide variety of technological applications. Despite numerous studies of these processes performed to date, the current understanding of them is far from complete. This is because the processes are multifaceted in the richness of phenomena that might occur, and are extremely difficult for theory to embrace all of them, or even some of them. In this project, the understanding of the structure and spectra of free and confined atoms and their interactions with incoming electromagnetic radiation or charged particles will be advanced. In the project, confined atoms of interest are defined as atoms which are embedded into hollow interiors of various gas-phase fullerenes Cn or other types of penetrable and impenetrable confinements with varying heights and widths, as well as positioned near planar or non-planar graphitic nano-structures. New trends in the cross sections of corresponding processes of photon absorption and collision of the incoming electrons with confined and free atoms will be unveiled. For free atoms, this will be achieved by accounting for the interactions mixing a 'pure' vacancy state (such, e.g., as 5s in Ba) or 'pure' incoming particle state with dominant (to be determined in the project) higher order continuous state excitations in a number of atoms, in the first hand in Ba and Mn; so far, the needed understanding is lacking. For confined atoms, new trends in their spectra will be unraveled by accounting for individual and combined effects brought about by the above specified confinements of different properties and geometry, by varying positions of the confined atom inside a confinement, and by accounting for multielectron interactions (electron correlation) in the atom itself. Hartree-Fock approximation, random phase approximation with exchange, methods of many-body perturbation theory, etc., will be employed in, or adjusted to, the stated studies. The intellectual merit of activities to be performed is determined by the fact that to date there is little knowledge on how the individual and combined effects of nano-scaled confinements of different symmetries (spherical, non-spherical, homogeneous, inhomogeneous, planar, non-planar, etc.) may alter the structure and spectra of confined in, or positioned near them atoms. Also, to date, there remains a lack of understanding of the interactions mixing pure vacancy/particle states in an atom with its higher order excitations. Moreover, results of the project will identify some of the most interesting and/or useful future measurements/calculations which could be performed, both for free and confined atoms, thereby contributing synergy to advancement of the field. On a broader impact scale, the involvement and active participation of undergraduate students in this project will strengthen integration of research and education at the University. Furthermore, the project will enhance the research infrastructure in the University. Results of research will be disseminated broadly to scientific community and general public for a broader awareness of science. Society will benefit from the performed activities by gaining new fundamental knowledge on phenomena of nature with important applications, and by the training of students who, early in their careers, will have acquired a unique professional experience for entry into graduate study in physics or scientific and engineering careers. All of the above will significantly contribute to the benefit, health, vitality of science and engineering, and the prosperity of society.