Atomic structure of FeII

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Atomic structure of FeII

• Jorge Troconis Manuel Bautista
• IVIC

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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

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

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Objective

• We want to construct a large, well optimized
  representation of FeII with AUTOSS

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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.

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Our approach

• New optimization functional based on energy
  differences between computted and experimental
  values
• New optimization technique based on the Conjugate
  Gradient Method

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Fe II expansion

• 23 configurations expansion with orbitals 1s, 2s,
  2p, 3s, 3p, 3d, 4s, 4p, 4d, 4f, 5s, 5p, 5d, 6s,
  6p

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GROUND STATE ENERGIES OF FeII
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Continue

• We are trying to use the new techniques to
  construct non-ortogonal basis sets
• We plan to use polarization potentials