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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
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:
FileName Lrecl Records Explanations
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
See also: J/A+A/529/A147 : Selenium ions photoionization cross sections (Sterling+, 2011) Byte-by-byte Description of file: table4.dat table5.dat
Bytes Format Units Label Explanations
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 alpha over T=100K (1) 43- 50 E8.2 cm3/s a(0.2) Rate coefficient alpha over T=200K (1) 52- 59 E8.2 cm3/s a(0.4) Rate coefficient alpha over T=400K (1) 61- 68 E8.2 cm3/s a(0.6) Rate coefficient alpha over T=600K (1) 70- 77 E8.2 cm3/s a(0.8) Rate coefficient alpha over T=800K (1) 79- 86 E8.2 cm3/s a(1.0) Rate coefficient alpha over T=1000K (1) 88- 95 E8.2 cm3/s a(1.2) Rate coefficient alpha over T=2000K (1) 97-104 E8.2 cm3/s a(1.4) Rate coefficient alpha over T=4000K (1) 106-113 E8.2 cm3/s a(1.6) Rate coefficient alpha over T=6000K (1) 115-122 E8.2 cm3/s a(1.8) Rate coefficient alpha over T=8000K (1) 124-131 E8.2 cm3/s a(10.) Rate coefficient alpha over T=10kK (1) 133-140 E8.2 cm3/s a(20.) Rate coefficient alpha over T=20kK (1) 142-149 E8.2 cm3/s a(40.) Rate coefficient alpha over T=40kK (1) 151-158 E8.2 cm3/s a(60.) Rate coefficient alpha over T=60kK (1) 160-167 E8.2 cm3/s a(80.) Rate coefficient alpha over T=80kK (1) 169-176 E8.2 cm3/s a(100) Rate coefficient alpha over T=100kK (1) 178-185 E8.2 cm3/s a(200) Rate coefficient alpha over T=200kK (1) 187-194 E8.2 cm3/s a(400) Rate coefficient alpha over T=400kK (1) 196-203 E8.2 cm3/s a(600) Rate coefficient alpha over T=600kK (1) 205-212 E8.2 cm3/s a(800) Rate coefficient alpha over T=800kK (1)
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). 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.
Acknowledgements: Nicholas Sterling, sterling(at) References: Sterling and Witthoeft, Paper I 2011A&A...529A.147S, Cat. J/A+A/529/A147
(End) Patricia Vannier [CDS] 10-Oct-2011
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