Polycyclic aromatic hydrocarbons with armchair edges and the 12.7 μm band

Candian, A.; Sarre, P. J.; Tielens, A. G. G. M.

Abstract

In this Letter, we report the results of density functional theory calculations on medium-sized neutral polycyclic aromatic hydrocarbon (PAH) molecules with armchair edges. These PAH molecules possess strong C–H stretching and bending modes around 3 μm and in the fingerprint region (10–15 μm), and also strong ring deformation modes around 12.7 μm. Perusal of the entries in the NASA Ames PAHs Database shows that ring deformation modes of PAHs are common, although generally weak. Therefore, we propose that armchair PAHs with N_C > 65 are responsible for the 12.7 μm aromatic infrared band in H II regions and discuss the astrophysical implications in the context of the PAH life cycle.

Citation

Candian, A., Sarre, P. J., & Tielens, A. G. G. M. (2014). Polycyclic aromatic hydrocarbons with armchair edges and the 12.7 μm band. Astrophysical Journal Letters, 791(1), Article L10. https://doi.org/10.1088/2041-8205/791/1/l10

• Journal Article Type: Article
• Acceptance Date: Jul 7, 2014
• Online Publication Date: Jul 25, 2014
• Publication Date: Aug 10, 2014
• Deposit Date: Feb 25, 2020
• Journal: Astrophysical Journal Letters
• Print ISSN: 2041-8213
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 791
• Issue: 1
• Article Number: L10
• DOI: https://doi.org/10.1088/2041-8205/791/1/l10
• Keywords: Space and Planetary Science; Astronomy and Astrophysics
• Public URL: https://nottingham-repository.worktribe.com/output/4034705
• Publisher URL: https://iopscience.iop.org/article/10.1088/2041-8205/791/1/L10