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开发一个完全相对论性的计算机代码，用于电子和光子与原子和离子的相互作用。 该代码已经在一些基准计算中使用，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放源代码许可证和指定网站向公众提供。 本科生将通过开发和测试该软件包的各个模块接受现代计算方法的培训。 这包括在大规模并行计算平台上运行代码，这些平台是由美国国家科学基金会支持的极限科学和工程发现环境（XSEDE）资源提供的。 B-样条R-矩阵（BSR）方法具有显着的优势，在过去的四十年中开发的，目前在世界范围内使用的著名的R-矩阵（紧耦合）代码套件。 具体而言，B样条基的数值特性产生高计算精度，并且采用非正交项依赖轨道集的能力允许紧凑的配置扩展。 在完成半相对论版本的并行化之后，该项目将支持完全相对论Dirac-Coulomb版本的并行实现的开发。 BSR碰撞代码还将与一套新的通用原子结构代码接口，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.