J/A+A/547/A33 Chemical reactions for a deuteration network (Vastel+, 2012)
Upper limit for the D2H+ ortho-to-para ratio in the prestellar core 16293E
(CHESS).
Vastel C., Caselli P., Ceccarelli C., Bacmann A., Lis D.C., Caux E.,
Codella C., Beckwith J.A., Ridley T.
<Astron. Astrophys. 547, A33 (2012)>
=2012A&A...547A..33V 2012A&A...547A..33V
ADC_Keywords: Models ; Molecular clouds ; Abundances
Keywords: astrochemistry - ISM: individual: 16293E - ISM: abundances -
line: identification - radiative transfer
Description:
The ground-state rotational ortho-D2H+(1,1,1-0,0,0) transition at
1476.6GHz in the prestellar core 16293E has been searched for with
the Herschel/HIFI instrument, within the CHESS (Chemical HErschel
Surveys of Star forming regions) Key Program. The line has not been
detected at the 21mK.km/s level (3 sigma integrated line intensity).
We used the ortho-H2D+ 110-111 transition and para-D2H+ 110-101
transition detected in this source to determine an upper limit on the
ortho-to-para D2H+ ratio as well as the para-D2H+/ortho-H2D+ ratio
from a non-LTE analysis. We then compared our chemical modeling with
the observations in order to estimate the CO depletion as well as the
H2 density and kinetic temperature at the position observed. The
chemical network is provided in the kida.dat file.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
kida.dat 89 3574 Adapted KIDA database
(Kinetic data for Astrochemistry)
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See also:
J/A+A/517/A21 : Sensitivity analysis list of chemical reactions (Wakelam+ 2010)
Byte-by-byte Description of file: kida.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- R1 Reactant #1
10- 17 A8 --- R2 Reactant #2
19- 26 A8 --- P1 Product #1
28- 35 A8 --- P2 Product #2
37- 44 A8 --- P3 Product #3
46- 53 A8 --- P4 Product #4
55- 63 E9.3 --- alpha α for rate coefficient (2) (1)
65- 74 E10.3 --- beta β for rate coefficient (2)
76- 85 E10.3 K gamma γ for rate coefficient (2)
88- 89 I2 --- itype [0-13] Type of reaction (3)
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Note (1): Unit depends on the type of reaction ("itype" column).
For types 0 and 2 to 12, the unit is cm3/s.
For types 1 and 13, unit is s-1.
See http://www.physics.ohio-state.edu/~eric/research.html
Note (2): See http://www.physics.ohio-state.edu/~eric/research.html for
the formula to compute the rate coefficient according to the type.
Note (3): itype as follows:
0 = Gas-grain interaction, electron-grain recombination (old version)
1 = Cosmic ray ionization. A(J)=scaling factor
2 = Ion-molecule reactions and charge exchange reactions
3 = Negative ion - neutral species reactions
4 = Radiative association: ion-neutral
5 = Electron ejection: negative ion - neutral
6 = Neutral + neutral --> ion + electron (only one reaction)
7 = Neutral + Neutral chemical reaction
8 = Neutral + Neutral radiative association
9 = Dissociative recombination
10 = Radiative recombination (No dissociation) atomic, molecular ion + e
11 = Positive-ion .vs. Negative-ion Recombination
12 = Electron attachment (neutral + e --> negative ion)
13 = Photo-ionization and photo-dissociation
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Acknowledgements:
Charlotte Vastel, cvastel(at)irap.omp.eu
Paola Caselli, p.caselli(at)leeds.ac.uk
(End) Patricia Vannier [CDS] 28-Sep-2012