Breit-Pauli R-matrix calculation for fine structure effective collision strengths from electron impact excitation of Mg IX

Context: Electron impact excitation collision strengths are required for analysing and interpreting stellar observations.
Aims: This calculation aims to provide fine-structure effective collision strengths for the Mg IX ion using a method that includes contributions from resonances.
Methods: A 26-state Breit-Pauli R-matrix calculation has been performed. The target states are represented by configuration interaction wavefunctions and consist of the 26 lowest {LS} states, having configurations 2s^2, 2s2p, 2p^2, 2s3s, 2s3p, 2s3d, 2p3s, 2p3p, and 2p3d. These target states give rise to 46 fine structure levels and 1035 possible transitions. The effective collision strengths are calculated by averaging the electron collision strengths over a Maxwellian distribution of electron velocities.
Results: The non-zero effective collision strengths for transitions between the fine structure levels are given for electron temperatures (T_e) in the range log₁₀ T_e(K) = 3.0-7.0. Values for selected transitions are given in this paper and links provided to the entire data set.

Table 6 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/493/697