Development of a General, Fully Relativistic, Parallelized B-Spline R-Matrix with Pseudo-States Program for Electron and Photon Interactions with Atoms, Ions, and Molecules

本项目的目的是利用b样条r矩阵（BSR）方法进一步开发一种通用的、有效的、完全相对论的电子和光子与原子、离子和分子相互作用的计算机代码。这种创新的方法比标准的r矩阵代码套件具有显著的优势，这些代码主要是在贝尔法斯特过去四十年中开发的，目前在全球范围内使用。具体来说，b样条基的优秀数值性质允许高计算精度，并且使用项相关轨道的非正交集的能力允许紧凑的构型展开。在目前的资助期内，现有的计算机代码将完全并行化，并将开发一套新的通用原子结构代码，该代码直接使用b样条作为BSR碰撞代码的改进接口。此外，将开发用于求解外区域紧密耦合方程的并行b样条代码，并将BSR程序的试点版本扩展到处理时间相关过程，如强短脉冲XUV激光与原子相互作用，将扩展到双电离和红外辐射。最后，将研究BSR方法在描述电子和光子与双原子分子相互作用方面的潜在应用。该项目的更广泛影响包括进一步开发一套非常成功的计算机程序，用于计算各种电子和光子驱动过程的精确原子数据。生产计算将集中在原子目标上，因为这些数据对于模拟天体物理和实验室等离子体、激光和行星大气的物理和化学具有关键价值。这项工作将支持许多实验项目，从工业照明系统到下一代同步加速器和自由电子激光器的基础研究。研究结果将在国际科学会议上发表，下一个版本的计算机代码将被编写出来并向公众开放。最后，本科生将通过开发和测试软件包的各个模块来进行培训。这包括在通过XSEDE资源提供的大规模并行计算平台上运行代码。

The purpose of this project is to further develop a general and effective, fully relativistic computer code for electron and photon interactions with atoms, ions, and molecules using the B-spline R-matrix (BSR) method. This innovative approach has significant advantages over the standard suite of R-matrix codes, mostly developed over the past four decades in Belfast and currently used worldwide. Specifically, the excellent numerical properties of a B-spline basis allow for high computational accuracy, and the ability to employ non-orthogonal sets of term-dependent orbitals allows for compact configuration expansions. During the current funding period, the existing computer code will be fully parallelized, and a new suite of general atomic structure codes will be developed, which directly use the B-spline as an improved interface to the BSR collision codes. Furthermore, a parallelized B-spline code to solve the close-coupling equations in the outer region will be developed, and a pilot version of the BSR program to treat time-dependent processes, such as intense short-pulse XUV laser-atom interactions, will be extended to double ionization and infrared radiation. Finally, the potential use of the BSR method to describe electron and photon interactions with diatomic molecules will be investigated.The broader impact of the project consists of the further development of a highly successful suite of computer programs to calculate accurate atomic data for a wide variety of electron- and photon-driven processes. The production calculations will focus on atomic targets, for which these data are of critical value to model the physics and chemistry of astrophysical and laboratory plasmas, lasers, and planetary atmospheres. This work will support many experimental projects ranging from industrial lighting systems to fundamental research performed at next-generation synchrotrons and free-electron lasers. The results will be presented at international scientific meetings, and the next version of the computer code will be written up and made available to the public. Finally, undergraduate students will be trained through developing and testing individual modules of the package. This includes running the code on massively parallel computing platforms provided through XSEDE resources.