Electron impact excitation of Ca-like iron Fe6+

Electron impact collision strengths, energy levels, oscillator strengths and spontaneous radiative decay rates are calculated for Fe VII using the Flexible Atomic Code. The configuration interactions included in the calculations of atomic structure and excitation are among the configurations of ([Ne])3s(2)3p(x)3d(y) (x + y = 8, x = 6 3), 3s(2)3p(6)3dnl (n = 4, 5, l = 0, 1,..., n-1), 3s(2)3p(6)4l4l' (l, l' = 0, 1, 2, 3), 3s3p(x)3d(y) (x + y = 9, x = 6, 5) and 3s(2)3p(5)3d(2)4s. Collision strengths are calculated at 20 scattered electron energies (5-6000 eV) for the energetically lowest 340 levels, with the highest excited states corresponding to levels belonging to the configuration of 3s(2)3p(6)3d5g. Effective collision strengths are obtained by assuming a Maxwellian electron velocity distribution at 15 temperatures from 10 to 500 eV. Comparison has been made with earlier theoretical collision strengths for the transitions within the ground configuration 3s(2)3p(6)3d(2), which are the only data available in the literature. Illustrative examples are given for some strong transitions belonging to the arrays of 3s(2)3p(6)3d(2)-3s(2)3p(5)3d(3),3s(2)3p(6)3d4p and 3s(2)3p(6)3d4f. The results show that the oscillator strengths and collision strengths are very sensitive to the configuration interaction. The complete data set is available electronically from http://www.astronomy.csbd.cn/EIE.