Issue |
A&A
Volume 675, July 2023
|
|
---|---|---|
Article Number | A25 | |
Number of page(s) | 32 | |
Section | Atomic, molecular, and nuclear data | |
DOI | https://doi.org/10.1051/0004-6361/202346645 | |
Published online | 28 June 2023 |
Photodissociation and photoionization of molecules of astronomical interest
Updates to the Leiden photodissociation and photoionization cross section database★
1
LISA UMR 7583 Université Paris-Est Créteil and Université de Paris, Institut Pierre et Simon Laplace,
61 Avenue du Général de Gaulle,
94010
Créteil, France
e-mail: hhrodmarsson@lisa.ipsl.fr
2
Laboratory for Astrophysics, Leiden Observatory, Leiden University,
PO Box 9513,
2300 RA
Leiden, The Netherlands
e-mail: hrodmarsson@strw.leidenuniv.nl
3
Leiden Observatory, Leiden University,
PO Box 9513,
2300 RA
Leiden, The Netherlands
e-mail: ewine@strw.leidenuniv.nl
4
Max-Planck-Institut für Extraterrestrische Physik,
Giessenbachstrasse 1,
85748
Garching, Germany
Received:
13
April
2023
Accepted:
16
May
2023
Context. Vacuum-ultraviolet (VUV) photons are important drivers of chemical processes in space. Thus, it is important to accurately characterize and constrain photorates in different radiation fields, via the photodissociation and photoionization cross sections of individual atoms and molecules. These have been available in the Leiden VUV photodissocation and photoionization cross section database.
Aims. Experimental and theoretical advances in the past decade or so have allowed multiple new cross sections to be obtained, particularly photoionization cross sections of radicals. The database is hereby updated by including these more recent cross sections and is also expanded with several astronomically relevant species.
Methods. The cross sections have been used to calculate photodissociation and photoionization rates in several different radiation fields as well as from cosmic-ray-induced VUV fluxes. The reduction of rates in shielded regions was calculated as a function of dust, molecular and atomic hydrogen, atomic carbon, and self-shielding column densities. The relative importance of these shielding types is molecule and atom dependent, as well as the assumed dust absorbance. All the data are publicly available from the Leiden VUV cross section database.
Results. The Leiden VUV cross section database has been updated with 14 new astrophysically relevant molecular species and 16 updates to previous entries. The database update is accompanied by a brief review of the basic physical processes, particularly photoionization processes which have not been reviewed in the context of previous database updates.
Key words: molecular data / ISM: molecules / photon-dominated region (PDR) / cosmic rays / dust, extinction / ultraviolet: ISM
Leiden photodissociation and photoionization cross section database: https://home.strw.leidenuniv.nl/~ewine/photo/
© 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.
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