The present calculation is part of an international collaboration known as the IRON Project (Hummer et al. 1993, referred to as Paper I) to obtain accurate collision rates for fine-structure transitions. Other papers in the series are given in the References section, while a complete list of IRON Project published papers and those in press is available at http://www.am.qub.ac.uk.
Collisionally induced transitions in Fe XXIV have been examined by
several authors in the past, most of whom used distorted wave (DW)
approximations with some allowance for relativistic effects. To our knowledge,
Hayes (1979) is the only person who has done a close-coupling
(CC) calculation for this ion. Her method, however, did not take account of
exchange and furthermore she only applied it to one energy above the
excitation thresholds of her target in order to confirm that the coupling
potentials could be neglected and that the DW approximation was sufficiently
reliable. Hayes found that her CC and DW collision strengths at this
particular energy agreed to within 5% for most transitions, except for
where the difference was about 20%.
The results given by Hayes (1979), Mann (1983), Younger (1987) and Zhang et al. (1990) are from DW calculations, which are similar in so far as they all take account of relativistic effects but ignore channel coupling and therefore show no resonance structure. For this reason we confine our comparison to the most recent work, namely that of Zhang et al. (1990).