The IR emission features - Emission from PAH molecules and amorphous carbon particlesTechniques for the assessment of the importance of the various forms of PAHs, and recent infrared observations concerning the PAH problem, are considered. Spectroscopic data suggest that the observed interstellar spectrum is due to both free molecule-sized PAHs producing the narrow features, and amorphous carbon particles contributing to the broad underlying components. Explanations for the multicomponent emission spectrum are discussed. A model of the emission mechanism for the example of chrysene is presented, and an exact treatment of the IR fluorescence from highly vibrationally excited large molecules shows that species containing 20-30 carbon atoms are responsible for the narrow features, although the spectra more closely resemble those of amorphous carbon particles. It is suggested that future emphasis should be placed on the spatial characteristics of the component spectra.
Document ID
19870054913
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Allamandola, L. J. (NASA Ames Research Center Moffett Field, CA, United States)
Tielens, A. G. G. M. (NASA Ames Research Center Moffett Field, CA, United States)
Barker, J. R. (Michigan, University Ann Arbor, United States)