Atomic data from the IRON project -: LII.: Electron excitation of Ni+24

This paper reports on the calculation of collision strengths for electron induced transitions in the beryllium-like ion Ni XXV whose ground state is 1s(2) 2s(2) S-1(0). We make use of the R-matrix method in conjunction with the intermediate frame coupling transformation (IFCT). The target has 98 fine structure states 1s(2) nl n' l' SLJ corresponding to n = 2 and n' = 2, 3, 4. Our calculation extends up to 440 Ry with respect to the ground state. In order to obtain reliable rate coefficients at high temperatures (T above 2 x 10(7) K) we have extended our collision strengths to much higher energies by using a variety of techniques, including use of Burgess's interactive code OmeUps. The effective collision strength Y is tabulated against log T for the 45 transitions linking the lowest 10 levels. We also give results for 5 transitions in the X-ray region which are needed in solar studies. The temperature range 6.3 x log T x 8.3 is centred on log T = 7.1 which is where this ion has its maximum coronal abundance.