J/A+A/535/A117 Low-charge ions charge transfer rate coeff. (Sterling+, 2011)
Atomic data for neutron-capture elements.
III. Charge transfer rate coefficients for low-charge ions of Ge, Se, Br, Kr,
Rb, and Xe.
Sterling N.C., Stancil P.C.
<Astron. Astrophys. 535, A117 (2011)>
=2011A&A...535A.117S 2011A&A...535A.117S
ADC_Keywords: Atomic physics
Keywords: atomic data - atomic processes - HII regions -
nucleosynthesis, abundances - planetary nebulae: general -
stars: evolution
Abstract:
We present total and final-state resolved charge transfer (CT) rate
coefficients for low-charge Ge, Se, Br, Kr, Rb, and Xe ions reacting
with neutral hydrogen over the temperature range 102-106K. Each of
these elements has been detected in ionized astrophysical nebulae,
particularly planetary nebulae. CT rate coefficients are a key
ingredient for the ionization equilibrium solutions needed to
determine total elemental abundances from those of the observed ions.
A multi-channel Landau Zener approach was used to compute rate
coefficients for projectile ions with charges q=2-5, and for
singly-charged ions the Demkov approximation was utilized.
Description:
Final state-resolved charge transfer rate coefficients are tabulated
for the first five ions of Ge, Se, Br, Kr, and Rb. Charge transfer
recombination rate coefficients (from the perspective of the
projectile ion Xq+) are given in Table 4, while those for charge
transfer ionization are given in Table 5. Recombination coefficients
are for collisions between the project and H+, while ionization
coefficients are for collisions with neutral hydrogen. Rate
coefficients are given for 20 temperatures spanning the range
102-106K.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 212 159 Final-state resolved charge transfer recombination
rate coefficients (cm3/s) for the reactions
Xq++H --> X(q-1)++H++δE
table5.dat 212 9 Final-state resolved charge transfer ionization
rate coefficients (cm3/s) for the reactions
X0+H+ --> X++H+δE
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See also:
J/A+A/529/A147 : Selenium ions photoionization cross sections (Sterling+, 2011)
Byte-by-byte Description of file: table4.dat table5.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- El Projectile element (Ge Se Br Kr Rb Xe)
4 I1 --- ion [0/5] Ionisation state
9- 32 A24 --- ExitC Exit channel
34- 41 E8.2 cm3/s a(0.1) Rate coefficient α over T=100K (1)
43- 50 E8.2 cm3/s a(0.2) Rate coefficient α over T=200K (1)
52- 59 E8.2 cm3/s a(0.4) Rate coefficient α over T=400K (1)
61- 68 E8.2 cm3/s a(0.6) Rate coefficient α over T=600K (1)
70- 77 E8.2 cm3/s a(0.8) Rate coefficient α over T=800K (1)
79- 86 E8.2 cm3/s a(1.0) Rate coefficient α over T=1000K (1)
88- 95 E8.2 cm3/s a(1.2) Rate coefficient α over T=2000K (1)
97-104 E8.2 cm3/s a(1.4) Rate coefficient α over T=4000K (1)
106-113 E8.2 cm3/s a(1.6) Rate coefficient α over T=6000K (1)
115-122 E8.2 cm3/s a(1.8) Rate coefficient α over T=8000K (1)
124-131 E8.2 cm3/s a(10.) Rate coefficient α over T=10kK (1)
133-140 E8.2 cm3/s a(20.) Rate coefficient α over T=20kK (1)
142-149 E8.2 cm3/s a(40.) Rate coefficient α over T=40kK (1)
151-158 E8.2 cm3/s a(60.) Rate coefficient α over T=60kK (1)
160-167 E8.2 cm3/s a(80.) Rate coefficient α over T=80kK (1)
169-176 E8.2 cm3/s a(100) Rate coefficient α over T=100kK (1)
178-185 E8.2 cm3/s a(200) Rate coefficient α over T=200kK (1)
187-194 E8.2 cm3/s a(400) Rate coefficient α over T=400kK (1)
196-203 E8.2 cm3/s a(600) Rate coefficient α over T=600kK (1)
205-212 E8.2 cm3/s a(800) Rate coefficient α over T=800kK (1)
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Note (1):
* For table4.dat: Each listed rate coefficient is the largest of the
radially-coupled CT rate coefficient from our MCLZ and Demkov calculations
and the canonical radiative CT rate coefficient 10-14cm3/s (Butler et al.
1977, Phys. Rev. A, 16, 500; Stancil & Zygelman 1996ApJ...472..102S 1996ApJ...472..102S).
Note that radiative CT does not occur for endoergic reactions.
* For table5.dat: For Ge, Se, and Br, the spin-orbit coupling rate
coefficient found for Cl+, 10-12cm3/s (Pradhan & Dalgarno, 1994,
Phys. Rev. A, 49, 960), is adopted as an upper limit when the rate from
radial coupling falls below that value. In the case of Se and Br, the SO rate
coefficient is adopted only for the dominant exit channels for SO coupling.
For CT reactions involving neutral Kr, Rb, and Xe, SO coupling is not
relevant and hence we set the rate coefficient to the canonical radiative CT
rate 10-14cm3/s (Butler et al. 1977, Phys. Rev. A, 16, 500) when the
radial coupling rate coefficient is smaller than that value.
Note that radiative CT does not occur for the endoergic reaction
Kr0+H+ --> Kr++H+δE.
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Acknowledgements:
Nicholas Sterling, sterling(at)pa.msu.edu
References:
Sterling and Witthoeft, Paper I 2011A&A...529A.147S 2011A&A...529A.147S, Cat. J/A+A/529/A147
(End) Patricia Vannier [CDS] 10-Oct-2011