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Comments: The Verner+1996 cross sections include contributions by all shells. In the code this total cross section is treated as the valence electron cross section (and other cross sections are put to zero). It is also assumed that all transitions occur to the ground state of the ion.

For nebular phase, only photoionizations from the ground state and meta-stable states play any role: for higher states a rough approximation like the hydrogen one is sufficient. The hydrogen approximation used is fully described in J12. Note that even if the first excited state is connected to the GS by an allowed transition, it is effectively metastable due to photon trapping - detailed cross sections for all first or even second excited states are desirable. I mark these as (E), with (T) meaning truly metastable.

HI (Latest doc J11):

  • GS : Verner et al. 1996
  • Meta-stable :
    • n=2 (E) : Bethe & Salpeter 1957 (incorrect reference to TOPBASE in J11)
  • Rest : Hydrogenic

HeI (Latest doc J11):

  • GS : Verner et al. 1996
  • Meta-stable :
    • 3S (T) : TOPBASE
    • 1S (T) : Hydrogenic
  • Rest up to 50 : Hydrogenic

HeII (Latest doc J11):

  • GS : Verner et al. 1996
  • Rest up to 50 : Hydrogenic

CI (Latest doc J11):

  • GS : Verner et al. 1996
  • Metastable:
    • 1D (T) : TOPBASE (Marked out)
    • 1S (T) : TOPBASE (Marked out)
    • 5S (T) : TOPBASE (Marked out)
  • Rest up to 50 : Hydrogenic

CII (Latest doc J11):

  • GS : Verner et al. 1996
  • Metastable:
    • 4P (T) : Hydrogenic
  • Rest up to 50 : Hydrogenic

NI (Latest doc J11):

  • GS : Verner et al. 1996
  • Metastable:
    • 2D (T) : TOPBASE
    • 2P (T) : Hydrogenic
    • 4P (E) : Hydrogenic
  • Rest up to 50 : Hydrogenic

TBC…

users/ajerkstrand/bound-free.txt · Last modified: 2015/09/28 15:31 by Anders Jerkstrand

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