Atomic Data from the IRON Project - XXXVI. Electron excitation of Be-like Fe xxiii between ${\rm 1s^2}\,2l_1\,2l_2\,SLJ$ and ${\rm 1s^2}\,2l_3\,2l_4\,S'L'J'$

Partial collision strengths for electron induced transitions in the beryllium-like ion Fe xxiii are calcu- lated using the Belfast R-matrix programs (Berrington et al. 1995). Our target has 98 ne structure states 1s 2 nln 0 l 0 SLJ corresponding to n =2 and n 0 =2 ; 3 ;4. 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 to- gether with JAJOM (Saraph 1978). When T 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 logT for transitions between the 2s 21 S 0 ,2 s2p 3 P o ; 1 ; 2 ,2 s2p 1 P o , 2p 23 P 0 ; 1 ; 2 ,2 p 21 D 2 and 2p 21 S 0 states. The tempera- ture range 6:3 log T 8:1 is centred on logT =7 : 1 which, according to Arnaud & Rothenflug (1985), is where Fe xxiii has maximum coronal abundance.