The ionisation state of PAHs in interstellar environments
E. Dartois and
Received 23 July 1996 / Accepted 23 December 1996
We present an ionisation model for Polycyclic Aromatic Hydrocarbon (PAH) molecules from which we determine the various size dependant ionisation states expected in different space environments. Maps of ionisation regimes are derived. They allow the estimate of the ionisation fraction of PAH for any given set of parameters (electron density, flux factor and temperature) assuming a typical PAH size of 50 carbon atoms. Moreover, a particular astronomical case is considered: the variation in ionisation states with depth in a typical dense cloud illuminated by a bright B1.5V star.
Key words: molecular data molecular processes ISM: molecules ISM: general
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© European Southern Observatory (ESO) 1997
Online publication: June 5, 1998