NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Laboratory Infrared Spectra of Polycyclic Aromatic Nitrogen Heterocycles: Quinoline, and Phenanthridine in Solid Argon and H2OPolycyclic aromatic hydrocarbons (PAHs) are common throughout the universe. Their detection and identification are based on telescopic infrared (IR) spectra compared with laboratory data. Polycyclic Aromatic Nitrogen Heterocycles (PANHs) are heterocyclic aromatics i.e., PAHs with carbon atoms replaced by a nitrogen atom. These molecules should be present in the interstellar medium, but have received relatively little attention. We present mid-IR spectra of two PANHs, quinoline (C9H7N), and phenanthridine (C13H9N) isolated in solid argon and frozen in solid H2O at 12 K, conditions yielding data directly comparable to astronomical observations. In contrast to simple PAHs, that do not interact strongly with solid H2O, the nitrogen atoms in PANHs are potentially capable of hydrogen bonding with H2O. Whereas the IR spectrum of phenanthridine in H2O is similar to that of the same compound isolated in an argon matrix, quinoline absorptions shift up to 16 cm(sup -1) (0.072 mm) between argon and H2O. Thus, astronomers will not always be able to rely on IR band positions of matrix isolated PANHs to correctly interpret the absorptions of PANHs frozen in H2O ice grains. Furthermore, our data suggest that relative band areas also vary, so determining column densities to better than a factor of 3 will require knowledge of the matrix in which the PANH is embedded and laboratory studies of relevant samples.
Document ID
20050010126
Document Type
Preprint (Draft being sent to journal)
Authors
Bernstein, M. P.
(NASA Ames Research Center Moffett Field, CA, United States)
Mattioda, A. L.
(NASA Ames Research Center Moffett Field, CA, United States)
Sandford, S. A.
(NASA Ames Research Center Moffett Field, CA, United States)
Hudgins, D. M.
(NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
August 22, 2013
Publication Date
January 1, 2004
Subject Category
Inorganic, Organic And Physical Chemistry
Funding Number(s)
OTHER: 344-58-21-02
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
No Preview Available