J/A+A/535/A117Low-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.117SADC_Keywords: Atomic physicsKeywords: atomic data - atomic processes - HII regions - nucleosynthesis, abundances - planetary nebulae: general - stars: evolutionAbstract: 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 X^{q+}) 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 10^{2}-10^{6}K.File Summary:

FileName Lrecl Records Explanations

ReadMe 80 . This file table4.dat 212 159 Final-state resolved charge transfer recombination rate coefficients (cm^{3}/s) for the reactions X^{q+}+H --> X^{(q-1)+}+H^{+}+δE table5.dat 212 9 Final-state resolved charge transfer ionization rate coefficients (cm^{3}/s) for the reactions X^{0}+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 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)

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^{-14}cm^{3}/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^{-12}cm^{3}/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^{-14}cm^{3}/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 Kr^{0}+H^{+}--> Kr^{+}+H+δE.

Acknowledgements: Nicholas Sterling, sterling(at)pa.msu.eduReferences: 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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