scholarly journals PAH clusters as interstellar very small grains

2019 ◽  
Vol 15 (S350) ◽  
pp. 415-416
Author(s):  
Joseph. E. Roser ◽  
Alessandra Ricca
Keyword(s):  
Infrared Spectroscopy ◽  
Interstellar Medium ◽  
Laboratory Experiments ◽  
Infrared Emission ◽  
Spectral Shifts ◽  
Matrix Isolation Spectroscopy ◽  
Candidate Species ◽  
Species Extrapolation ◽  
Small Grains ◽  
Argon Matrices

AbstractPAH clusters are one candidate species for the interstellar “very small grains” or “VSGs”, i.e., dust grains small enough to be stochastically heated and contribute to the aromatic infrared emission bands (AIBs). This possibility motivated laboratory experiments on the infrared spectroscopy of PAH clusters using matrix isolation spectroscopy. The spectral shifts due to PAH clustering in argon matrices provide clues for the AIB contribution from PAH clusters in the interstellar medium. Here we review results from a number of small PAH species, extrapolation to the much larger PAHs believed to be present in the interstellar medium, and the implications for a PAH cluster contribution to the VSG population.

Analytical Applications of Matrix Isolation Fourier Transform Infrared Spectroscopy

1982 ◽  
Vol 36 (4) ◽  
pp. 339-347 ◽  
Author(s):  
G. Mamantov ◽  
A. A. Garrison ◽  
E. L. Wehry
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Vibrational Spectroscopy ◽  
Matrix Isolation ◽  
Fourier Transform Infrared ◽  
Chromatographic Separations ◽  
Analytical Applications ◽  
Matrix Isolation Spectroscopy ◽  
Ft Ir

A review of analytical applications of matrix isolation Fourier transform infrared spectroscopy is presented. The characteristics of matrix isolation spectroscopy are discussed along with practical techniques for obtaining analytically useful results. A few studies relating to matrix isolation used in conjunction with Raman and conventional IR spectroscopy are reviewed. The majority of analytical applications of matrix isolation vibrational spectroscopy has entailed the use of FT-IR techniques. Qualitative and quantitative results from a number of sample types are presented. The coupling of matrix isolation vibrational spectroscopy with chromatographic separations is reviewed.

Infrared Spectroscopy of Diamondoid Molecules: New Insights into the Presence of Nanodiamonds in the Interstellar Medium

2007 ◽  
Vol 661 (2) ◽  
pp. 919-925 ◽  
Author(s):  
Olivier Pirali ◽  
Michel Vervloet ◽  
Jeremy E. Dahl ◽  
Robert M. K. Carlson ◽  
A. G. G. M. Tielens ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Interstellar Medium

scholarly journals The origin and evolution of interstellar organics

2008 ◽  
Vol 4 (S251) ◽  
pp. 35-44 ◽  
Author(s):  
Jean E. Chiar ◽  
Yvonne J. Pendleton
Keyword(s):  
Interstellar Medium ◽  
Interstellar Dust ◽  
Laboratory Experiments ◽  
Ir Detector ◽  
Space Telescope ◽  
Origin And Evolution ◽  
Past Work ◽  
Dust Composition ◽  
Absorption Features ◽  
Dust Absorption

AbstractOver the last decade, we have made great strides in better understanding dust composition and evolution in dense clouds and the diffuse interstellar medium (ISM). Thanks to improvements in IR detector sensitivity on ground-based telescopes and the Spitzer Space Telescope mission, we are no longer limited to a handful of bright background stars in order to study dust composition in quiescent dense clouds and the diffuse ISM. More thorough sampling of lines of sight in these regions has highlighted the dichotomy of the nature and composition of dust in these environments. In addition, successes in recreating interstellar processes and dust-analogs in the laboratory have helped us to understand the differences in dust absorption features we observe in the ISM. In this article, we focus on the organic components of interstellar dust, reviewing past work and highlighting the most recent observations and laboratory experiments.

scholarly journals Supernova Remnant Shocks in an Inhomogeneous Interstellar Medium

1988 ◽  
Vol 101 ◽  
pp. 205-222 ◽  
Author(s):  
Christopher F. McKee
Keyword(s):  
Interstellar Medium ◽  
Supernova Remnant ◽  
Circumstellar Matter ◽  
Infrared Emission ◽  
Circumstellar Material ◽  
Hot Gas ◽  
Wide Range ◽  
Low Mass ◽  
Late Stages ◽  
Intercloud Medium

AbstractThe inhomogeneity of the interstellar medium (ISM) has a profound effect on the propagation of the interstellar shock generated by a supernova and on the appearance of the resulting supernova remnant (SNR). Low mass supernovae produce remnants that interact with the “pristine” ISM, which has density inhomogeneities (clouds) on a wide range of scales. The shock compresses and accelerates the clouds it encounters; inside the blast wave, the clouds are hydrodynamically unstable, and mass is injected from the clouds into the intercloud medium. Embedded clouds interact thermally with the shock also, adding mass to the hot intercloud medium via thermal evaporation or subtracting it via condensation and thermal instability. Mass injection into the hot intercloud medium, whether dynamical or thermal, leads to infrared emission as dust mixes with the hot gas and is thermally sputtered. The remnants of massive supernovae interact primarily with circumstellar matter and with interstellar material which has been processed by the ionizing radiation and wind of the progenitor star. After passing through any circumstellar material which may be present, the shock encounters a cavity which tends to “muffle” the SNR. The remnants of massive supernovae therefore tell us more about the late stages of the evolution of massive stars than about the ISM.

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