J/A+A/529/A147 Photoionization cross sections of Selenium ions (Sterling+, 2011)
Atomic data for neutron-capture elements.
I. Photoionization and recombination properties of low-charge selenium ions.
Sterling N.C., Witthoeft M.C.
<Astron. Astrophys. 529, A147 (2011)>
=2011A&A...529A.147S 2011A&A...529A.147S
ADC_Keywords: Atomic physics
Keywords: atomic data - atomic processes - HII regions -
nucleosynthesis, abundances - planetary nebulae: general -
stars: evolution
Abstract:
We present multi-configuration Breit-Pauli AUTOSTRUCTURE calculations
of distorted-wave photoionization (PI) cross sections, and total and
partial final-state resolved radiative recombination (RR) and
dielectronic recombination (DR) rate coefficients for the first six
ions of the trans-iron element Se. These calculations were motivated
by the recent detection of Se emission lines in a large number of
planetary nebulae. Se is a potentially useful tracer of
neutron-capture nucleosynthesis, but accurate determinations of its
abundance in photoionized nebulae have been hindered by the lack of
atomic data governing its ionization balance. Our calculations were
carried out in intermediate coupling with semi-relativistic radial
wavefunctions. PI and recombination data were determined for levels
within the ground configuration of each ion, and experimental PI
cross-section measurements were used to benchmark our results. For DR,
we allowed Δn=0 core excitations, which are important at
photoionized plasma temperatures.
Description:
'Direct' and 'Direct and resonant' photoionization cross sections are
tabulated for neutral and the first five ions of Se. Note that
photoexcitation-autoionization resonances are not included in these
data files. Names of the files are given by pxd.dat
(px.dat), e.g., se2+pxd.dat (se2+px.dat) for photoionization of
Se2+ ions.
Comments are indicated by '#' in the first column of a line.
The first two lines of a file are header information indicating the
number of photon targets (ground state and metastable states in the
ground configuration, with 1 the lowest energy) and number of
energies. The photoionization cross section of each state is preceded
by a comment giving the energy above the ground state (or the total
energy, in the case of the ground state), the total energy of the
target state, and the energy-order of that state (1 = ground state,
2 = first excited state, etc.).
All energies are reported in Rydbergs, and cross sections in megabarns
(10-18cm2).
Total and partial final state resolved dielectronic recombination rate
coefficients are tabulated for the first six ions of Se, in the ADAS
adf09 and adf48 formats. Names of the files are given by
adf09_.dat (adf48_), e.g., adf09_se2+.dat
(adf48_se2+.dat) gives dielectronic recombination data for Se2+
forming Se+. These files are available in adf subdirectory.
The format of these files is complex, and beyond the scope of this
README file. The reader is referred to
http://amdpp.phys.strath.ac.uk/tamoc/RR/RR_web/appxa-09.pdf for a
complete description of the adf09 and adf48 files format.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 223 21 Configuration-interaction expansions used for each
Se ion
se0_pxd.dat 30 225005 Direct Se0 photoionization cross section
se1_pxd.dat 30 225005 Direct Se+ photoionization cross section
se2_pxd.dat 30 225005 Direct Se2+ photoionization cross section
se3_pxd.dat 30 180004 Direct Se3+ photoionization cross section
se4_pxd.dat 30 45001 Direct Se4+ photoionization cross section
se5_pxd.dat 30 45001 Direct Se5+ photoionization cross section
se0_px.dat 78 292046 Direct and resonant Se0 photoionization cross section
se1_px.dat 78 346274 Direct and resonant Se+ photoionization cross section
se2_px.dat 78 358941 Direct and resonant Se2+ photoionization cross section
se3_px.dat 78 164862 Direct and resonant Se3+ photoionization cross section
se4_px.dat 78 74055 Direct and resonant Se4+ photoionization cross section
se5_px.dat 78 98750 Direct and resonant Se5+ photoionization cross section
adf/* . 12 Total and partial final state resolved dielectronic
recombination rate coefficients for six ions of Se,
in the ADAS adf09 and adf48 formats
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- Ion Ion designation
6- 11 A6 --- Set Configuration set (Small, Medium or Large)
13- 15 I3 --- Nlev Number of levels
16 A1 --- n_Nlev [b] Note (1)
18-223 A206 --- Conf Configurations
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Note (1): b: Although the same CI expansion was utilized for the small and
medium sets of Se6+, the scaling parameters of the medium set were optimized
differently: the configurations 3d95d, 3d96d, and 3d97d were included in
the configuration list to determine scaling parameters, but removed in the
final structure calculation.
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Byte-by-byte Description of file (#): *xd.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
3- 16 E14.8 Ry EP [0/100] Photon energy
21- 30 E10.4 Mbarn Xint Photoionization cross section (in 10-18cm2)
--------------------------------------------------------------------------------
Byte-by-byte Description of file (#): *x.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
3- 16 E14.8 Ry EP Photon energy relative to the ground state
19- 32 E14.8 Ry E(N0) Photon energy relative to the initial state (1)
34- 48 E15.8 Ry E0 Ejected electron energy relative to the
ground state
50- 64 E15.8 Ry E Ejected electron energy relative to the
initial state
69- 78 E10.4 Mbarn Xint Photoionization cross section (in 10-18cm2)
--------------------------------------------------------------------------------
Note (1): E(N0)=EP for the ground state.
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Acknowledgements:
N. Sterling, sterling(at)pa.msu.edu
(End) Patricia Vannier [CDS] 28-Feb-2011