Theory of Atomic Collisions

原子碰撞理论

• 批准号: 8918713
• 负责人: Joseph Macek
• 金额: $ 23.33万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-01-01 至 1993-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8918713&HistoricalAwards=false
• 关键词: Theory; Atomic; Collisions

This research will probe strongly interacting atomic systems to develop practical computational schemes for treating them. There are five projects to be undertaken: (1.) Perturbation Series of Strongly Interacting Atoms and Ions. The new perturbation series developed for strongly interacting systems will be formally extended to treat ionization and applied to compute cross sections for the interaction of highly ionized atoms with low Z targets. Some connections of this work and QED have recently been discovered and it is expected they will be explored further. 2. New Time Dependent Variational Principle. A new time dependent variational principle akin to the Schwinger principle for time independent problems will be applied to some of the problems of part 1. The advantage of the variational formulation is to be able to derive higher order approxi- mations to the distorting potential used in the strong potential Born calculations for highly ionized systems. 3. Hyperspherical Expansions. The hyperspherical expansion developed earlier will be applied to the scattering of H+ on deuterium as a test of the "translation factor free" theory. Particular attention will be paid to electron transfer reactions. All that remains is the actual coupled channel calculation using the computed wave functions and potential curves. 4. Saddle Point Effects In Secondary Electron Spectra. Work on saddle point effects in secondary electron spectra will be continued. New approximations to the electron propagator will be developed which contain rotational effects and the new propagator will be used to compute an approximate wave function for the final state. The primary difficulty is the numerical evaluation of the multiple integrals but this seems quite tractable. There are close connections with experimental work at Nebraska and Tennessee. 5. Alignment and Orientation in the Abramov Model. Alignment and orientation parameters are a very sensitive test of collisional approximations. The Abromov model has been developed to compute these parameters for states formed by electron capture at low velocities. The model will be applied and tested against existing experiment. The hope is to stimulate further measurements. There is close co-operation with the experimental groups at Oak Ridge, Kansas State, and other highly charged ion sources such as that at Cornell.

这项研究将探测强相互作用的原子 系统开发实用的计算方案， 对待他们。将开展五个项目： （1.） 强相互作用原子的微扰级数 和离子。 新的扰动级数发展为强 交互系统将正式扩展到治疗 电离和应用于计算截面的 高电离原子与低Z靶的相互作用。 一些 这项工作和量子电动力学的联系最近被发现 预计将对其进行进一步探索。 2.新的时变原理 新的时间 类似于Schwinger原理的相关变分原理 对于时间无关的问题将适用于一些 第一部分的问题。 变分法的优点 公式是能够推导出更高的阶近似- 在强电磁场中使用的扭曲势的方法 高度电离系统的势玻恩计算。 3.超球面扩张 超球面 扩展开发较早将适用于散射 作为"无翻译因子"的测试 理论 将特别注意电子转移 反应. 剩下的就是实际的耦合通道 用计算出的波函数和势函数进行计算 曲线. 4.二次电子能谱中的鞍点效应。 研究二次电子能谱中的鞍点效应， 请继续。 电子传播子的新近似 将开发包含旋转效果和新的 传播算子将用于计算近似波函数 最后的状态。 主要的困难是数字 多重积分的计算，但这似乎相当 听话 与实验工作有密切联系 在内布拉斯加州和田纳西州。 5.阿布拉莫夫模型中的对齐和方向。 对齐和方向参数是一个非常敏感的测试 碰撞近似。 Abromov模型已经被 开发来计算这些参数的国家形成的， 低速电子俘获。 该模型将应用于 并与现有的实验进行了对比。 希望能 促进进一步的测量。 密切合作 与堪萨斯州橡树岭的实验组， 其他高电荷离子源，如康奈尔大学。