Electron collisions with Fe-peak elements: Fe IV
I. Forbidden transitions: 3d – 3d4s and 3d – 3d4p manifolds
School of Mathematics and Physics, Queen's University of Belfast, Belfast BT7 1NN, UK e-mail: email@example.com
2 Computational Science and Engineering Department, CCLRC Daresbury Laboratory, Keckwick Lane, Daresbury, Warrington WA4 4AD, UK
Accepted: 26 September 2005
Electron-impact excitation collision strengths of the Fe-peak element Fe IV are calculated in the close-coupling approximation using the parallel R-matrix program PRMAT. One hundred and eight LS – coupled states arising from the , and configurations of Fe IV, are retained in the present calculations. Accurate multi-configuration target wavefunctions are employed with the aid of electron promotions and a correlation orbital. The effective collision strengths required in the analysis of astrophysically important lines in the Fe IV spectra, are obtained by averaging the electron collision strengths for a wide range of incident electron energies, over a Maxwellian distribution of velocities. Results are tabulated for forbidden transitions between the , and the manifolds for electron temperatures (Te in degrees Kelvin) in the range that are applicable to many laboratory and astrophysical plasmas. The present results provide new results for forbidden lines in the Fe IV spectrum studied here.
Key words: atomic data / atomic processes
© ESO, 2006