Future Proof Parallelism for Electron-Atom Scattering Codes on the XT4

Electron collisions with atoms were among the earliest problems studied using quantum mechanics. However, the accurate computation of much of the data required in astrophysics and plasma physics still presents huge computational challenges, even on the latest generation of high-performance computer architectures, such as the Cray XT series. In recent years a suite of parallel programs based on the 'R-matrix' ab initio approach to variational solution of the many-electron Schrodinger equation has been developed and has enabled much accurate scattering data to be produced. However, future calculations will require substantial increases in both the numbers of channels and scattering energies involved in the R-matrix propagations. This paper describes how these computational challenges are being addressed by improving the parallel performance of the PRMAT code on the Cray XT4.