Abstract
A distorted-wave program is being developed for calculating the excitation of few-electron ions by electron impact. It utilises the exchange approximation to represent the exact initial-state wavefunction in the T-matrix expression for the excitation amplitude. The program has been implemented for excitation of the 21,3(SkP) states of two-electron ions. Comparison is made with other results where available. The first part of the paper discusses some of the astrophysical applications of these cross sections as well as the motivation and requirements of the calculational methodology.