Photon- and Electron-Driven Atomic Collision Processes: General Theory and Accurate Numerical Calculations

这个项目涉及光（主要是激光）和带电粒子（主要是电子）与原子和离子的相互作用。这些结果对于理解基本的碰撞动力学具有重要意义，它们也满足了对精确原子数据的迫切实际需要，以模拟恒星，等离子体，激光和行星大气的物理。该项目的短脉冲强激光部分需要在数值时空网格上精确解出时变薛定谔方程。随着目前计算资源的快速发展，这样的研究现在可以在现实中进行，而不是理想化的模型系统。这项工作对于促进亚微观反应的成像和控制的进一步发展是重要的，而这反过来又有望通过从物理学到化学并最终生物学产生广泛的影响。另一个话题是在电子-原子碰撞中产生的量子纠缠。这一领域在量子信息技术方面具有应用潜力。本项目支持世界范围内的许多实验工作，并将培养一名博士后和一些研究生。大多数数值计算将基于非微扰r矩阵（紧密耦合）方法，使用高度灵活的b样条实现非正交轨道集，以及使用各种基于网格的方法和基函数展开的时变薛定谔方程的直接解。对于用强烈的atto/飞秒激光脉冲进行复杂原子的单电离和双电离，这些方法将以这样一种方式结合起来，即“大问题”的各个部分可以以高效和优化的方式处理。一个例子是利用b样条r矩阵方法中的时间无关的多电子库仑和偶极矩阵元素在一种传播方案中用于求解时间依赖的薛定谔方程。这种一般策略将扩展到处理涉及内壳层的双电离。重点将放在数值方法的测试和结果的可视化上，这两者都是学生参与的理想选择。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project deals with the interaction of light (mostly lasers) and charged particles (mostly electrons) with atoms and ions. The results are of importance for the understanding of fundamental collision dynamics, and they also fulfill the urgent practical need for accurate atomic data to model the physics of stars, plasmas, lasers, and planetary atmospheres. The short-pulse intense-laser part of the project requires accurate solutions of the time-dependent Schroedinger equation on a numerical space-time grid. With the rapid advances currently seen in computational resources, such studies can now be conducted for realistic, as opposed to idealized, model systems. This work is important to facilitate further developments in the imaging and control of submicroscopic reactions, which in turn are expected to have broad impact by reaching out from physics to chemistry and ultimately biology. Another topic is quantum entanglement created in electron-atom collisions. This area has potential for applications in quantum information technology. Many experimental efforts worldwide are supported through the present project, which will also train a post-doctoral associate and a number of research students.Most of the numerical calculations will be based upon the non-perturbative R-matrix (close-coupling) method using a highly flexible B-spline implementation with non-orthogonal orbital sets, as well as direct solutions of the time-dependent Schroedinger equation using various grid-based approaches and basis-function expansions. For single and double ionization of complex atoms by intense atto/femto-second laser pulses, the methods will be combined in such a way that individual parts of the "big problem" can be treated in highly efficient and optimized ways. One example is the use of time-independent multi-electron Coulomb and dipole matrix elements from the B-spline R-matrix method in a propagation scheme for the solution of the time-dependent Schroedinger equation in a few-cycle laser pulse. This general strategy will be extended to the treatment of double ionization involving inner shells. Much emphasis will be placed on the testing of numerical methods and the visualization of the results, both of which are ideal for student involvement.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.