1. Atomic structure of FeII Jorge Troconis & Manuel Bautista IVIC

2. Introduction FeII is one of the most important species in astronomy from UV through IR Several calculations of atomic structure and A-values have been reported (e.g Garstang 1962, Nussbaumer & Storey 1988, Zeippen 1997) Various groups around the world continue working on this system

4. The FeII spectra is photoexcited by Lyα in a variety of nebulae Proper calculations of FeII spectra require models with ~1000 levels (including up to 5p, 5d, and 6s configurations)

5. Objective We want to construct a large, well optimized representation of FeII with AUTOSS

6. Problems Optimization of large systems is difficult because: –They are strictly based on overall statistics –Numeric optimization techniques fail in some cases - AUTOSS does not allow for minimization of fine-structure levels including relativistic corrections.

7. Our approach New optimization functional based on energy differences between computted and experimental values New optimization technique based on the Conjugate Gradient Method

8. Fe II expansion 23 configurations expansion with orbitals 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 4d, 4f, 5s, 5p, 5d, 6s, 6p

9. GROUND STATE ENERGIES OF FeII MethodE(Ry) Original-2524.3455 Original + MVD-2541.8055 New functioanal-2524.3468 New functional+MVD-2541.8062 Optim. Conju. Gradient.2524.3513 Optim. Conju. Gradient+MVD-2541.8051

12. Continue… We are trying to use the new techniques to construct non-ortogonal basis sets We plan to use polarization potentials