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Anharmonicity and the interstellar polycyclic aromatic hydrocarbon infrared emission spectrum

Journal Article · · Astrophys. J.; (United States)
DOI:https://doi.org/10.1086/184861· OSTI ID:6269512
The hypothesis that interstellar infrared emission originates from vibrationally excited polycyclic aromatic hydrocarbons (PAHs) requires that emission can arise from all vibrational levels that are energetically accessible. Due to anharmonicity, the emission from the upper vibrational levels is shifted to longer wavelengths from that of the v = 1-0 transition. It is shown that structure in the 3-micron region is readily and quantitatively explained by emission from upper vibrational levels of excited PAHs that contain a maximum of 20-30 carbon atoms. The asymmetrical broadening of the 11.3-micron emission band may also be due to anharmonicity. 21 references.
Research Organization:
Michigan Univ., Ann Arbor; NASA, Ames Research Center, Moffett Field, CA; California Univ., Berkeley
OSTI ID:
6269512
Journal Information:
Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 315; ISSN ASJOA
Country of Publication:
United States
Language:
English