Polycyclic aromatic hydrocarbons and the unidentified infrared emission bands - Auto exhaust along the Milky Way

1985 ◽  
Vol 290 ◽  
pp. L25 ◽  
Author(s):  
L. J. Allamandola ◽  
A. G. G. M. Tielens ◽  
J. R. Barker
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Milky Way ◽  
Infrared Emission ◽  
Polycyclic Aromatic

scholarly journals The Infrared Emission Features and Polycyclic Aromatic Hydrocarbons

1989 ◽  
Vol 135 ◽  
pp. 129-140
Author(s):  
L. J. Allamandola
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Related Species ◽  
Infrared Emission ◽  
Polycyclic Aromatic

The infrared evidence which supports the PAH hypothesis is briefly summarized. Rather than presenting a general discussion of these assignments, this paper focuses on the spectroscopic issues raised by recent observational and experimental developments. These issues include: the position and profile of the “1310” cm−1(“7.7” μm) feature, the position and intensities of the bands in the 910-710 cm−1(11-14 μm) region, the newly detected 1900 cm−1(5.3 μm) band, and the spatial and spectral variations in the 3000 cm−1(3 μm) region as well as in the 12 and 25 μm IRAS bands. It is concluded that the infrared evidence for interstellar PAHs and PAH-related species is compelling.

scholarly journals Processing of polycyclic aromatic hydrocarbons in evolved planetary nebulae

2011 ◽  
Vol 7 (S283) ◽  
pp. 462-463
Author(s):  
Ryou Ohsawa ◽  
Takashi Onaka ◽  
Itsuki Sakon ◽  
Issei Yamamura ◽  
Mikako Matsuura ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Near Infrared ◽  
Planetary Nebulae ◽  
Infrared Emission ◽  
Chemical Processing ◽  
Evolutionary Phase ◽  
Polycyclic Aromatic ◽  
Stellar Temperatures ◽  
Evolution Sequence

AbstractWe investigate the infrared emission bands from Polycyclic Aromatic Hydrocarbons (PAHs) in Galactic planetary nebulae (PNe). PAHs in PNe are assumed to be in transition from circumstellar to interstellar PAHs. We select 15 evolved PNe taking account of effective stellar temperatures and obtain infrared spectra of PNe from AKARI (2.5–5 μm) and Spitzer (5–14 μm) observations. Their evolutionary phase is estimated using [SIV]10.51/[NeII]12.81. We find that the near-infrared PAH bands are significantly enhanced along with stellar evolution sequence. We also find that the ratio of 3.4 to 3.3 μm bands is enhanced. The enhancement might indicate some chemical processing, such as hydrogenation, on small PAHs.

scholarly journals Interstellar polycyclic aromatic hydrocarbons: Spectroscopy, photofragmentation and photoproducts

2019 ◽  
Vol 15 (S350) ◽  
pp. 353-355
Author(s):  
Jordy Bouwman ◽  
Jerry Kamer ◽  
Pablo Castellanos ◽  
Michał Bulak ◽  
Sanjana Panchagnula ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Density Functional ◽  
Ion Trap ◽  
Infrared Emission ◽  
Functional Theory ◽  
Mid Infrared ◽  
Radiation Fields ◽  
Polycyclic Aromatic ◽  
Spectroscopic Signatures

AbstractUbiquitous strong mid-infrared emission bands are observed towards many objects and are attributed to interstellar Polycyclic Aromatic Hydrocarbons (PAHs). PAHs are ionized, or even dissociate, when exposed to strong interstellar radiation fields. By means of ion trap mass spectrometry, light-induced dissociation patterns of PAH cations are measured and the mid-infrared spectroscopic signatures of the parent ion and its dissociation products are characterized. These results are then combined with density functional theory (DFT) calculations to obtain insight into the dissociation characteristics of interstellar PAHs at a molecular level.

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