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PAH-related Very Small Grains in photodissociation regions: implications from molecular simulations
Rapacioli M., Spiegelman F., Joalland B., Simon A., Mirtschink A. et al
EAS Publications Series 46 (2011) 223-234 - http://hal.archives-ouvertes.fr/hal-00843485
PAH-related Very Small Grains in photodissociation regions: implications from molecular simulations
Mathias Rapacioli1, Fernand Spiegelman1, Baptiste Joalland1, Aude Simon1, André Mirtschink1, Christine Joblin2, J. Montillaud2, O. Berné, D. Talbi3
1 :  LCPQ - Laboratoire de Chimie et Physique Quantiques
Université Paul Sabatier (UPS) - Toulouse III – CNRS : UMR5626
118 Route de Narbonne Bât. 3R1 b4 Toulouse 31062 Toulouse cedex 9
2 :  CESR - Centre d'étude spatiale des rayonnements
CNRS : UMR5187 – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier (UPS) - Toulouse III
9 Av du colonel Roche - BP 4346 31028 TOULOUSE CEDEX 4
3 :  LUPM - Laboratoire Univers et Particules de Montpellier
CNRS : UMR5299 – Université Montpellier II - Sciences et techniques – IN2P3
Université de Montpellier II Place Eugène Bataillon - CC 72 34095 Montpellier Cédex 05
Modélisation, Agrégats, Dynamique
The analysis of mid-IR emission suggests that a population of PAH-related very small grains containing a few hundreds of atoms are present in the deep regions of molecular clouds, although no specific species has been identified yet. In this review, we discuss several candidates for these grains: neutral and ionised PAH clusters and complexes of PAHs with Si atoms. The theoretical modelling of the properties of such molecular complexes or nanograins is a challenging task. We first present an overview of quantum chemistry derived models which can be efficiently used on-the-fly in extensive sampling of the potential energy surfaces, as required by structural optimization, classical molecular dynamics or Monte Carlo algorithms. From the simulations, various observables can be determined, such as the binding energies, finite temperature IR spectra, nucleation and evaporation rates. We discuss the relevance of those candidates in the molecular clouds photodissociation regions and propose constrains and perspectives for the nature and size of those very small grains.

EAS Publications Series
Publisher EDP Sciences
ISSN 1633-4760 (eISSN : 1638-1963)
Articles dans des revues avec comité de lecture