Electron excitation of Be-like Fe XXIII between 1s2
SLJ and 1s2 SLJ |

M.C. Chidichimo, V. Zeman, J.A. Tully and K.A. Berrington |

Astronomy & Astrophysics Supplement Series, 1999, Vol.137, pp.175-184 |

Partial collision strengths for electron induced transitions in the
beryllium-like ion Fe XXIII are calculated using the Belfast
*R*-matrix programs (Berrington et al. 1995). Our target has 98 fine
structure states 1s
*SLJ* corresponding to
and
. The present calculation is carried out for electron
impact energies in the range 3.15 to 350 Ry. Below 115.185 Ry, corresponding
to the highest excited state of our model ion, we use the Breit-Pauli
version of the *R*-matrix code. For energies between 116 and 350 Ry we
use the non-relativistic *LS*-coupling version of the *R*-matrix
code together with JAJOM (Saraph 1978). When exceeds about ten million
degrees one needs to take account of contributions to the thermally averaged
collision strength coming from electrons with energies in excess
of 350 Ry. We discuss a way of estimating these contributions. Values of
are computed and tabulated as functions of for
transitions between the 2s S,2s2pP
,
2s2pP, 2p P,2p D and
2p S states. The temperature range
is
centred on which according to Arnaud & Rothenflug (1985), is
where Fe XXIII has maximum coronal abundance.