/ftp/cats/A+A/648/A76



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J/A+A/648/A76     O(3P) + H2(v, j)-->OH + H:OH reactions     (Veselinova+, 2021)
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	table1.dat tables1.dat
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Query from: http://vizier.cds.unistra.fr/viz-bin/VizieR?-source=J/A+A/648/A76
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drwxr-xr-x 36 cats archive 4096 Jun 28 2021 [Up] drwxr-xr-x 3 cats archive 234 Jan 12 2023 [TAR file] -rw-r--r-- 1 cats archive 480 Dec 19 2022 .message -r--r--r-- 1 cats archive 12034 Apr 15 2021 ReadMe -r--r--r-- 1 cats archive 2640 Apr 15 2021 table1.dat [txt] [txt.gz] [fits] [fits.gz] [html] -r--r--r-- 1 cats archive 220910 Mar 9 2021 tables1.dat.gz [txt] [txt.gz] [fits] [fits.gz] [html]
Beginning of ReadMe : 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 (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 H_2_ and evaluate the impact on the abundance of OH in interstellar regions strongly irradiated by far-UV photons, where H_2_ 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(^3^P)+H_2_(v,j)-->OH+H, with H_2_ 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 H_2_, although even for high vibrational states of H_2_ (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+H_2_, 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 cm^3^/s. The header shows the specific state whose k(T) is depicted in that column.