| Issue |
A&A
Volume 680, December 2023
|
|
|---|---|---|
| Article Number | A113 | |
| Number of page(s) | 4 | |
| Section | Atomic, molecular, and nuclear data | |
| DOI | https://doi.org/10.1051/0004-6361/202348272 | |
| Published online | 19 December 2023 | |
Rate coefficients for the rotational de-excitation of OCS by collision with He★
Instituto de Ciencias Aplicadas, Facultad de Ingeniería, Universidad Autónoma de Chile,
Av. Pedro de Valdivia 425,
7500912
Providencia,
Santiago,
Chile
e-mail: otoniel.denis@uautonoma.cl
Received:
13
October
2023
Accepted:
18
October
2023
Context. In typical molecular clouds, analyzing the physicochemical conditions with nonlocal thermodynamic equilibrium models requires knowledge of the collisional rate coefficients between the detected molecule and the most common colliders in the interstellar medium (ISM); for example H2, He, and H. The OCS molecule has been widely observed in the ISM. However, the collision data available for this species were calculated using a potential energy surface (PES) that shows differences with surfaces presented recently.
Aims. The main goal of this work is to report a new set of rate coefficients for the collision of OCS with He based on a new PES computed at a high level of theory.
Methods. We developed an analytical PES using a large set of ab initio energies calculated using the coupled cluster with single, double, and perturbative triple excitations (CCSD(T)) method at the completed basis set limit for the OCS+He complex. We used this surface in close-coupling calculations, and computed a new set of collisional rate coefficients for OCS and He.
Results. We compare the de-excitation rate coefficients with previously available data. Furthermore, we observe a |Δj| = 1 propensity rule. Finally, we report a set of rate coefficients for the lower 39 rotational states of OCS, which is the largest set determined to date for this collision.
Key words: astrochemistry / molecular data / molecular processes / scattering / ISM: molecules
Rotational de-excitation rate coefficients (Table 2) are available at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/680/A113
© The Authors 2023
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This article is published in open access under the Subscribe to Open model. Subscribe to A&A to support open access publication.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.