Interstellar dehydrogenated PAH anions: vibrational spectra

Buragohain, Mridusmita; Pathak, Amit; Sarre, Peter; Kishor Gour, Nand

Abstract

Interstellar Polycyclic Aromatic Hydrocarbon (PAH) molecules exist in diverse forms depending on the local physical environment. Formation of ionized PAHs (anions and cations) is favourable in the extreme conditions of the ISM. Besides in their pure form, PAHs are also likely to exist in substituted forms; for example, PAHs with functional groups, dehydrogenated PAHs etc. A dehydrogenated PAH molecule might subsequently form fullerenes in the ISM as a result of ongoing chemical processes. This work presents a Density Functional Theory (DFT) calculation on dehydrogenated PAH anions to explore the infrared emission spectra of these molecules and discuss any possible contribution towards observed IR features in the ISM. The results suggest that dehydrogenated PAH anions might be significantly contributing to the 3.3 μm region. Spectroscopic features unique to dehydrogenated PAH anions are highlighted that may be used for their possible identification in the ISM. A comparison has also been made to see the size effect on spectra of these PAHs.

Citation

Buragohain, M., Pathak, A., Sarre, P., & Kishor Gour, N. (2018). Interstellar dehydrogenated PAH anions: vibrational spectra. Monthly Notices of the Royal Astronomical Society, 474(4), 4594-4602. https://doi.org/10.1093/mnras/stx3060

• Journal Article Type: Article
• Acceptance Date: Nov 23, 2017
• Online Publication Date: Nov 27, 2017
• Publication Date: Mar 11, 2018
• Deposit Date: Jan 11, 2018
• Publicly Available Date: Jan 11, 2018
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 474
• Issue: 4
• Pages: 4594-4602
• DOI: https://doi.org/10.1093/mnras/stx3060
• Keywords: Lines and bands; ISM: molecules; ISM: astrochemistry; Physical data and processes; Molecular processes
• Public URL: https://nottingham-repository.worktribe.com/output/919646
• Publisher URL: https://academic.oup.com/mnras/article/474/4/4594/4668421
• Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2017 The authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.