Photodissociation of interstellar ArH+

Abstract

Aims. Following the recent detection of 36ArH+ in the Crab nebula spectrum, we have computed the photodissociation rate of ArH+ in order to constrain the physical processes at work in this environment. Methods. Photodissociation cross sections of ArH+ are computed in an ab initio approach including explicit account of spin-orbit coupling. Results. We report the photodissociation cross section of ArH+ as a function of wavelength. Photodissociation probabilities are derived for different impinging radiation fields.The photodissociation probability of for a very small unshielded cloud surrounded on all sides by the unshielded InterStellar Radiation Field (ISRF) model described by Draine (1978) is equal to 9.9e-12 s-1 and 1.9e-9 s-1 in the Crab nebula conditions. The dependence on the visual extinction is obtained by using the Meudon Photon Dominated Region (PDR) code and corresponding analytical fits are provided. Conclusions. These data will help to produce a realistic chemical network to interpret the observations. Photodissociation of ArH+ is found to be moderate and the presence of this molecular ion is mainly dependent on the molecular fraction

11 pages, 6 Figures, Accepted in Astronomy Astrophysics

References in corpus (4)

• Photoprocesses in protoplanetary disks
• Detection of a Noble Gas Molecular Ion, {36}ArH^+, in the Crab Nebula
• The penetration of FUV radiation into molecular clouds
• The Fractional Ionization of the Warm Neutral Interstellar Medium

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• Modelling the ArH${}^{+}$ emission from the Crab Nebula
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• Theoretical study of ArH+ dissociative recombination and electron-impact vibrational excitation
• Exploring the Possibility of Identifying Hydride and Hydroxyl Cations of Noble Gas Species in the Crab Nebula Filament
• Extending the view of ArH+ chemistry in diffuse clouds
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• Fate and detectability of rare gas hydride ions in nova ejecta: A case study with nova templates
• Radiative Charge Transfer Between the Helium Ion and Argon
• OH${}^{+}$ emission from cometary knots in planetary nebulae