Mean-Field Techniques for Atomic Collision Theory (Physics)

原子碰撞理论（物理）的平均场技术

• 批准号: 8711139
• 负责人: Jose Garcia
• 金额: $ 21.95万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-08-01 至 1991-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8711139&HistoricalAwards=false
• 关键词: Mean; Field; Techniques; Atomic; Collision

Initial application of mean-field theory to atomic collisions has indicated that it handles well some of the difficulties encountered in basis expansion techniques for ion- atom scattering. Some of the strengths of the theory are (i) that it provides intuitive pictures for model development and mechanism elucidation, (ii) the ease with which continuum intermediate states are included, and (iii) the fact that many- body effects are included in the transition matrix elements. Since the initial results were so encouraging, it is proposed to broaden the generality and scope of this technique to make it applicable to a wider variety of problems. A proper framework has been developed and tested to provide instantaneous coupling from the quantum electronic degrees of freedom to the classical nuclear degrees of freedom. When this has been incorporated into the ion-atom collision program, and some three-dimensional capability has been developed, it will be possible to address a variety of topics such as chemical reactions and ion-surface scattering, in addition to problems in low-energy (adiabatic) ion-atom charge exchange. This research group will apply its well-established techniques for numerical solution of the time-dependent Schrodinger equation to obtain a better understanding of the interaction between an atom or ion and a metal surface. The objective of the proposed work is to bring together state-of- the-art descriptions for the time-dependent behavior of the atom (TDHF), the trajectory (CQC) and the surface (jellium) to obtain the best available description of atom-surface interactions. The group is uniquely qualified to make significant contributions to charge exchange scattering from surfaces in a relatively short time. This research effort should provide reliable values for some of the parameters used in current models, guidance as to the range of validity of certain models, and intuitive pictures for thinking about the atom-surface interaction.

平均场理论在原子碰撞中的初步应用表明，它很好地解决了离子原子散射基展开技术中遇到的一些困难。该理论的一些优势是：(i)它为模型开发和机制阐明提供了直观的图片，（ii）包含连续介质中间状态的容易程度，以及（iii）在过渡矩阵元素中包含多体效应的事实。由于最初的结果是如此令人鼓舞，因此建议扩大这种技术的普遍性和范围，使其适用于更广泛的各种问题。开发并测试了一个适当的框架，以提供量子电子自由度与经典核自由度之间的瞬时耦合。当它被纳入到离子原子碰撞程序中，并且一些三维能力已经开发出来，除了低能（绝热）离子原子电荷交换问题之外，还可以解决各种主题，如化学反应和离子表面散射。该研究小组将运用其成熟的技术对时变薛定谔方程进行数值求解，以更好地理解原子或离子与金属表面之间的相互作用。所提出的工作的目标是将原子（TDHF），轨迹（CQC）和表面（jellum）的时间依赖性行为的最新描述结合起来，以获得原子-表面相互作用的最佳可用描述。该小组是唯一有资格在相对较短的时间内对表面电荷交换散射做出重大贡献的人。这项研究工作将为当前模型中使用的一些参数提供可靠的值，为某些模型的有效性范围提供指导，并为思考原子表面相互作用提供直观的图像。