Graphical R-matrix atomic collision environment (GRACE): the problem specification stage

In this paper we introduce the concept of a graphical R-matrix atomic collision environment (GRACE). GRACE couples the graphical capability of powerful workstations with the processing power of supercomputers to provide an environment for the study of atomic collision properties and processes. At the core of GRACE is a new generation R-matrix program package, which is used to compute properties characterising electron atom and electron ion collisions. One of the motivations behind the project is to render this package simple to use by novice and experienced users alike, thereby significantly improving its usefulness to the physics community. GRACE is composed of a problem specification stage, a computation stage, and an interpretation stage. The focus of this paper is a description of the X Window graphical user interface which constitutes the problem specification stage of GRACE.