The UCL distorted wave code Original Research Article

The DW code of University College London computes collision strengths and reactance matrix elements in LS coupling for excitation of atoms and positive ions by electron impact in a partial wave expansion. A multiconfigurational target serves as the scatterer; the partial waves are central field solutions to a distorted wave (DW) approximation. The DW program is run by linking two source codes: program COLALG and a modifying module called DWMODS. In stand-alone mode COLALG creates a file to the requirements of the electron collission program IMPACT, passing on target data and the angular expansion coefficients of collisional symmetries. Linked with DWMODS and program writes a reactance matrix file directly readable by JaJOM; the output file OMEGA is compatible with a similar file created by the QUB R-matrix code. Collisional details can be extracted depending upon the printing level. The UCL macro-processor with the source codes as input creates ForTran 77 files; apart from replacing size parameters is switches parts of code on and off depending upon directives. For