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Collisional excitation of singly deuterated ammonia NH_2D by H_2

Daniel, F. and Faure, A. and Wiesenfeld, L. and Roueff, E. and Lis, D. C. and Hily-Blant, P. (2014) Collisional excitation of singly deuterated ammonia NH_2D by H_2. Monthly Notices of the Royal Astronomical Society, 444 (3). pp. 2544-2554. ISSN 0035-8711. doi:10.1093/mnras/stu1670.

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The availability of collisional rate coefficients with H_2 is a pre-requisite for interpretation of observations of molecules whose energy levels are populated under non-local thermodynamical equilibrium conditions. In the current study, we present collisional rate coefficients for the NH2D/para-H_2(J2 = 0, 2) collisional system, for energy levels up to J_τ = 7_7 (E_u ∼ 735 K) and for gas temperatures in the range T = 5–300 K. The cross-sections are obtained using the essentially exact close-coupling (CC) formalism at low energy and at the highest energies, we used the coupled-states (CS) approximation. For the energy levels up to Jτ = 42 (E_u ∼ 215 K), the cross-sections obtained through the CS formalism are scaled according to a few CC reference points. These reference points are subsequently used to estimate the accuracy of the rate coefficients for higher levels, which is mainly limited by the use of the CS formalism. Considering the current potential energy surface, the rate coefficients are thus expected to be accurate to within 5 per cent for the levels below J_τ = 42, while we estimate an accuracy of 30 per cent for higher levels.

Item Type:Article
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URLURL TypeDescription Paper
Roueff, E.0000-0002-4949-8562
Lis, D. C.0000-0002-0500-4700
Alternate Title:Collisional excitation of singly deuterated ammonia NH2D by H2
Additional Information:© 2014 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2014 August 13. Received 2014 July 22. All (or most of) the computations presented in this paper were performed using the CIMENT infrastructure (, which is supported by the Rhône–Alpes region (GRANT CPER07_13 CIRA: DL support for this work was provided by NASA (Herschel OT funding) through an award issued by JPL/Caltech. This work has been supported by the Agence Nationale de la Recherche (ANR-HYDRIDES), contract ANR-12-BS05-0011-01 and by the CNRS national programme ‘Physico-Chimie du Milieu Interstellaire’.
Funding AgencyGrant Number
Agence Nationale pour la Recherche (ANR)ANR-12-BS05-0011-01
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Subject Keywords:molecular data; molecular processes; scattering
Issue or Number:3
Record Number:CaltechAUTHORS:20141120-161157971
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Official Citation:Daniel, F., Faure, A., Wiesenfeld, L., Roueff, E., Lis, D. C., & Hily-Blant, P. (2014). Collisional excitation of singly deuterated ammonia NH2D by H2. Monthly Notices of the Royal Astronomical Society, 444(3), 2544-2554. doi: 10.1093/mnras/stu1670
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:52024
Deposited By: Jason Perez
Deposited On:21 Nov 2014 17:36
Last Modified:10 Nov 2021 19:19

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