J/A+A/648/A76 O(3P) + H2(v, j)-->OH + H:OH reactions (Veselinova+, 2021)
Quantum study of reaction O(3P) + H2(v, j)-->OH + H:OH formation in strongly
UV-irradiated gas.
Veselinova A., Agundez M., Goicoechea J.R., Menendez M., Zanchet A.,
Verdasco E., Jambrina P.G., Aoiz F.J.
<Astron. Astrophys. 648, A76 (2021)>
=2021A&A...648A..76V 2021A&A...648A..76V (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics ; Interstellar medium ; Ultraviolet
Keywords: astrochemistry - molecular processes - photon-dominated region -
ISM: molecules
Abstract:
The reaction between atomic oxygen and molecular hydrogen is an
important one in astrochemistry as it regulates the abundance of the
hydroxyl radical and serves to open the chemistry of oxygen in diverse
astronomical environments. However, the existence of a high activation
barrier in the reaction with ground state oxygen atoms limits its
efficiency in cold gas. In this study we calculate the dependence of
the reaction rate coefficient on the rotational and vibrational state
of H2 and evaluate the impact on the abundance of OH in interstellar
regions strongly irradiated by far-UV photons, where H2 can be
efficiently pumped to excited vibrational states.
We use a recently calculated potential energy surface and carry out
time-independent quantum mechanical scattering calculations to compute
rate coefficients for the reaction O(3P)+H2(v,j)-->OH+H, with
H2 in vibrational states v=0-7 and rotational states j=0-10. We find
that the reaction becomes significantly faster with increasing
vibrational quantum number of H2, although even for high vibrational
states of H2 (v=4-5) for which the reaction is barrierless, the rate
coefficient does not strictly attain the collision limit and still
maintains a positive dependence with temperature. We implemented the
calculated state-specific rate coefficients in the Meudon PDR code to
model the Orion Bar PDR and evaluate the impact on the abundance of
the OH radical. We find the fractional abundance of OH is enhanced by
up to one order of magnitude in regions of the cloud corresponding to
AV=1.3-2.3, compared to the use of a thermal rate coefficient for
O+H2, although the impact on the column density of OH is modest, of
about 60%. The calculated rate coefficients will be useful to model
and interpret JWST observations of OH in strongly UV-illuminated
environments.
Description:
Table S1 includes the raw QM/QCT rate coefficients for v=0-7, j=0-10
that were fitted to obtain the parameters shown in Table 1 of the main
manuscript.
The first column of S1 shows the Temperature (K) with columns 2-89
showing k(T) v=0-7, j=0-10 with units of cm3/s. The header shows the
specific state whose k(T) is depicted in that column.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 29 88 Rate coefficient parameters for O(3P)+H2(v,j)
tables1.dat 1334 496 Raw QM/QCT rate coefficients for v=0-7, j=0-10
that were fitted to obtain the parameters
shown in Table 1
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 I1 --- v [0/7] Initial H2 state v value
3- 4 I2 --- j [0/10] Initial H2 state j value
7- 15 E9.4 cm2/s alpha α coefficient (1)
17- 22 F6.4 --- beta β coefficient (1)
24- 29 F6.1 --- gamma(K) γ(K) coefficient (1)
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Note (1): The parameters α, β, and γ are obtained by fitting
the QM/QCT rate coefficients (tables1) to the expression
k(T)=α(T/300)^βexp(-γ/T), where T is the temperature in
degrees Kelvin. The fits are valid for the temperature range 100-3000K,
except for v=0, j=0-3, in which case the fits are only valid in the 200-3000K
temperature range.
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Byte-by-byte Description of file: tables1.dat
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Bytes Format Units Label Explanations
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1- 14 E14.9 K T Temperature
16- 29 E14.9 cm3/s v0j0 Raw QM/QCT rate coefficient for v=0,j=0
31- 44 E14.9 cm3/s v0j1 Raw QM/QCT rate coefficient for v=0,j=1
46- 59 E14.9 cm3/s v0j2 Raw QM/QCT rate coefficient for v=0,j=2
61- 74 E14.9 cm3/s v0j3 Raw QM/QCT rate coefficient for v=0,j=3
76- 89 E14.9 cm3/s v0j4 Raw QM/QCT rate coefficient for v=0,j=4
91- 104 E14.9 cm3/s v0j5 Raw QM/QCT rate coefficient for v=0,j=5
106- 119 E14.9 cm3/s v0j6 Raw QM/QCT rate coefficient for v=0,j=6
121- 134 E14.9 cm3/s v0j7 Raw QM/QCT rate coefficient for v=0,j=7
136- 149 E14.9 cm3/s v0j8 Raw QM/QCT rate coefficient for v=0,j=8
151- 164 E14.9 cm3/s v0j9 Raw QM/QCT rate coefficient for v=0,j=9
166- 179 E14.9 cm3/s v0j10 Raw QM/QCT rate coefficient for v=0,j=10
181- 194 E14.9 cm3/s v1j0 Raw QM/QCT rate coefficient for v=1,j=0
196- 209 E14.9 cm3/s v1j1 Raw QM/QCT rate coefficient for v=1,j=1
211- 224 E14.9 cm3/s v1j2 Raw QM/QCT rate coefficient for v=1,j=2
226- 239 E14.9 cm3/s v1j3 Raw QM/QCT rate coefficient for v=1,j=3
241- 254 E14.9 cm3/s v1j4 Raw QM/QCT rate coefficient for v=1,j=4
256- 269 E14.9 cm3/s v1j5 Raw QM/QCT rate coefficient for v=1,j=5
271- 284 E14.9 cm3/s v1j6 Raw QM/QCT rate coefficient for v=1,j=6
286- 299 E14.9 cm3/s v1j7 Raw QM/QCT rate coefficient for v=1,j=7
301- 314 E14.9 cm3/s v1j8 Raw QM/QCT rate coefficient for v=1,j=8
316- 329 E14.9 cm3/s v1j9 Raw QM/QCT rate coefficient for v=1,j=9
331- 344 E14.9 cm3/s v1j10 Raw QM/QCT rate coefficient for v=1,j=10
346- 359 E14.9 cm3/s v2j0 Raw QM/QCT rate coefficient for v=2,j=0
361- 374 E14.9 cm3/s v2j1 Raw QM/QCT rate coefficient for v=2,j=1
376- 389 E14.9 cm3/s v2j2 Raw QM/QCT rate coefficient for v=2,j=2
391- 404 E14.9 cm3/s v2j3 Raw QM/QCT rate coefficient for v=2,j=3
406- 419 E14.9 cm3/s v2j4 Raw QM/QCT rate coefficient for v=2,j=4
421- 434 E14.9 cm3/s v2j5 Raw QM/QCT rate coefficient for v=2,j=5
436- 449 E14.9 cm3/s v2j6 Raw QM/QCT rate coefficient for v=2,j=6
451- 464 E14.9 cm3/s v2j7 Raw QM/QCT rate coefficient for v=2,j=7
466- 479 E14.9 cm3/s v2j8 Raw QM/QCT rate coefficient for v=2,j=8
481- 494 E14.9 cm3/s v2j9 Raw QM/QCT rate coefficient for v=2,j=9
496- 509 E14.9 cm3/s v2j10 Raw QM/QCT rate coefficient for v=2,j=10
511- 524 E14.9 cm3/s v3j0 Raw QM/QCT rate coefficient for v=3,j=0
526- 539 E14.9 cm3/s v3j1 Raw QM/QCT rate coefficient for v=3,j=1
541- 554 E14.9 cm3/s v3j2 Raw QM/QCT rate coefficient for v=3,j=2
556- 569 E14.9 cm3/s v3j3 Raw QM/QCT rate coefficient for v=3,j=3
571- 584 E14.9 cm3/s v3j4 Raw QM/QCT rate coefficient for v=3,j=4
586- 599 E14.9 cm3/s v3j5 Raw QM/QCT rate coefficient for v=3,j=5
601- 614 E14.9 cm3/s v3j6 Raw QM/QCT rate coefficient for v=3,j=6
616- 629 E14.9 cm3/s v3j7 Raw QM/QCT rate coefficient for v=3,j=7
631- 644 E14.9 cm3/s v3j8 Raw QM/QCT rate coefficient for v=3,j=8
646- 659 E14.9 cm3/s v3j9 Raw QM/QCT rate coefficient for v=3,j=9
661- 674 E14.9 cm3/s v3j10 Raw QM/QCT rate coefficient for v=3,j=10
676- 689 E14.9 cm3/s v4j0 Raw QM/QCT rate coefficient for v=4,j=0
691- 704 E14.9 cm3/s v4j1 Raw QM/QCT rate coefficient for v=4,j=1
706- 719 E14.9 cm3/s v4j2 Raw QM/QCT rate coefficient for v=4,j=2
721- 734 E14.9 cm3/s v4j3 Raw QM/QCT rate coefficient for v=4,j=3
736- 749 E14.9 cm3/s v4j4 Raw QM/QCT rate coefficient for v=4,j=4
751- 764 E14.9 cm3/s v4j5 Raw QM/QCT rate coefficient for v=4,j=5
766- 779 E14.9 cm3/s v4j6 Raw QM/QCT rate coefficient for v=4,j=6
781- 794 E14.9 cm3/s v4j7 Raw QM/QCT rate coefficient for v=4,j=7
796- 809 E14.9 cm3/s v4j8 Raw QM/QCT rate coefficient for v=4,j=8
811- 824 E14.9 cm3/s v4j9 Raw QM/QCT rate coefficient for v=4,j=9
826- 839 E14.9 cm3/s v4j10 Raw QM/QCT rate coefficient for v=4,j=10
841- 854 E14.9 cm3/s v5j0 Raw QM/QCT rate coefficient for v=5,j=0
856- 869 E14.9 cm3/s v5j1 Raw QM/QCT rate coefficient for v=5,j=1
871- 884 E14.9 cm3/s v5j2 Raw QM/QCT rate coefficient for v=5,j=2
886- 899 E14.9 cm3/s v5j3 Raw QM/QCT rate coefficient for v=5,j=3
901- 914 E14.9 cm3/s v5j4 Raw QM/QCT rate coefficient for v=5,j=4
916- 929 E14.9 cm3/s v5j5 Raw QM/QCT rate coefficient for v=5,j=5
931- 944 E14.9 cm3/s v5j6 Raw QM/QCT rate coefficient for v=5,j=6
946- 959 E14.9 cm3/s v5j7 Raw QM/QCT rate coefficient for v=5,j=7
961- 974 E14.9 cm3/s v5j8 Raw QM/QCT rate coefficient for v=5,j=8
976- 989 E14.9 cm3/s v5j9 Raw QM/QCT rate coefficient for v=5,j=9
991-1004 E14.9 cm3/s v5j10 Raw QM/QCT rate coefficient for v=5,j=10
1006-1019 E14.9 cm3/s v6j0 Raw QM/QCT rate coefficient for v=6,j=0
1021-1034 E14.9 cm3/s v6j1 Raw QM/QCT rate coefficient for v=6,j=1
1036-1049 E14.9 cm3/s v6j2 Raw QM/QCT rate coefficient for v=6,j=2
1051-1064 E14.9 cm3/s v6j3 Raw QM/QCT rate coefficient for v=6,j=3
1066-1079 E14.9 cm3/s v6j4 Raw QM/QCT rate coefficient for v=6,j=4
1081-1094 E14.9 cm3/s v6j5 Raw QM/QCT rate coefficient for v=6,j=5
1096-1109 E14.9 cm3/s v6j6 Raw QM/QCT rate coefficient for v=6,j=6
1111-1124 E14.9 cm3/s v6j7 Raw QM/QCT rate coefficient for v=6,j=7
1126-1139 E14.9 cm3/s v6j8 Raw QM/QCT rate coefficient for v=6,j=8
1141-1154 E14.9 cm3/s v6j9 Raw QM/QCT rate coefficient for v=6,j=9
1156-1169 E14.9 cm3/s v6j10 Raw QM/QCT rate coefficient for v=6,j=10
1171-1184 E14.9 cm3/s v7j0 Raw QM/QCT rate coefficient for v=7,j=0
1186-1199 E14.9 cm3/s v7j1 Raw QM/QCT rate coefficient for v=7,j=1
1201-1214 E14.9 cm3/s v7j2 Raw QM/QCT rate coefficient for v=7,j=2
1216-1229 E14.9 cm3/s v7j3 Raw QM/QCT rate coefficient for v=7,j=3
1231-1244 E14.9 cm3/s v7j4 Raw QM/QCT rate coefficient for v=7,j=4
1246-1259 E14.9 cm3/s v7j5 Raw QM/QCT rate coefficient for v=7,j=5
1261-1274 E14.9 cm3/s v7j6 Raw QM/QCT rate coefficient for v=7,j=6
1276-1289 E14.9 cm3/s v7j7 Raw QM/QCT rate coefficient for v=7,j=7
1291-1304 E14.9 cm3/s v7j8 Raw QM/QCT rate coefficient for v=7,j=8
1306-1319 E14.9 cm3/s v7j9 Raw QM/QCT rate coefficient for v=7,j=9
1321-1334 E14.9 cm3/s v7j10 Raw QM/QCT rate coefficient for v=7,j=10
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Acknowledgements:
Marcelino Agundez, marcelino.agundez(at)csic.es
(End) Patricia Vannier [CDS] 09-Mar-2021