Development of a General and Effective Program B-Spline R-Matrix program for Charged-Particle and Photon Collisions with Atoms, Ions, and Molecules

该项目的目的是继续发展一个完全相对论的计算机代码，用于电子和光子与原子和离子的相互作用。该代码已经用于许多基准计算，以获得对基础研究和实际应用至关重要的高度精确的原子数据。特别是，该代码被用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。计算机代码将通过开源许可和指定网站向公众开放。本科生将通过开发和测试软件包的各个模块来训练现代计算方法。这包括在由美国国家科学基金会支持的极限科学与工程发现环境（XSEDE）资源提供的大规模并行计算平台上运行代码。b样条r矩阵（BSR）方法与过去四十年来开发并目前在世界范围内使用的众所周知的r矩阵（紧密耦合）代码套件相比具有显着优势。具体地说，b样条基的数值性质产生了很高的计算精度，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。在完成了半相对论版本的并行化后，该项目将支持开发完全相对论狄拉克-库仑版本的并行实现。BSR碰撞代码还将与一套新的通用原子结构代码进行接口，这些代码直接使用b样条展开。

The purpose of this project is to continue the development of a fully relativistic computer code for electron and photon interactions with atoms and ions. The code has already been employed in a number of benchmark calculations to obtain highly accurate atomic data of critical importance for fundamental research and practical applications. In particular, the code is being used to model the physics and chemistry of astrophysical and laboratory plasmas, lasers, and planetary atmospheres. The computer code will be made available to the general public through an open-source license and a designated website. Undergraduate students will be trained in modern computational methods through developing and testing individual modules of the package. This includes running the code on massively parallel computing platforms provided through the eXtreme Science and Engineering Discovery Environment (XSEDE) resources supported by the National Science Foundation. The B-spline R-matrix (BSR) approach has significant advantages over the well-known suite of R-matrix (close-coupling) codes that were developed over the past four decades and are currently used worldwide. Specifically, the numerical properties of a B-spline basis yield high computational accuracy and the ability to employ non-orthogonal sets of term-dependent orbitals allows for compact configuration expansions. After having completed the parallelization of the semi-relativistic version, this project will support the development of a parallel implementation of the fully relativistic Dirac-Coulomb version. The BSR collision codes will also be interfaced with a new suite of general atomic structure codes, which use B-spline expansions directly.