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arXiv · 1501.06811

The 11.2 $μ$m emission of PAHs in astrophysical objects

A. Candian·P. J. Sarre
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Abstract

The 11.2 $μ$m emission band belongs to the family of the `Unidentified' Infrared (UIR) emission bands seen in many astronomical environments. In this work we present a theoretical interpretation of the band characteristics and profile variation for a number of astrophysical sources in which the carriers are subject to a range of physical conditions. The results of Density Functional Theory (DFT) calculations for the solo out-of-plane (OOP) vibrational bending modes of large polycyclic aromatic hydrocarbon (PAH) molecules are used as input for a detailed emission model which includes the temperature and mass dependence of PAH band wavelength, and a PAH mass distribution that varies with object. Comparison of the model with astronomical spectra indicates that the 11.2 $μ$m band asymmetry and profile variation can be explained principally in terms of the mass distribution of neutral PAHs with a small contribution from anharmonic effects.

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A. Candian, P. J. Sarre. 2015-01-27. The 11.2 $μ$m emission of PAHs in astrophysical objects. https://doi.org/10.1093/mnras%2Fstv192

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