Collisional excitation of doubly deuterated ammonia ND2H by helium
Résumé
Context: Doubly deuterated ammonia has been found in various dense interstellar environments.
Aims: We extend our previous study of singly deuterated ammonia NH2D collisional excitation by helium to doubly deuterated ammonia ND2H.
Methods: The presence of two deuterium atoms in the system modifies the symmetry and the expansion coefficients of the intermolecular potential energy surface. We establish the corresponding collision equations.
Results: Cross sections are calculated in the coupled-state (CS) approximation and collisional rate coefficients are given between 5 and 100 K, a range of temperatures that is relevant to interstellar conditions.
Conclusions: .These results may be used to interpret the available millimeter and submillimeter observations of ND2H.
Aims: We extend our previous study of singly deuterated ammonia NH2D collisional excitation by helium to doubly deuterated ammonia ND2H.
Methods: The presence of two deuterium atoms in the system modifies the symmetry and the expansion coefficients of the intermolecular potential energy surface. We establish the corresponding collision equations.
Results: Cross sections are calculated in the coupled-state (CS) approximation and collisional rate coefficients are given between 5 and 100 K, a range of temperatures that is relevant to interstellar conditions.
Conclusions: .These results may be used to interpret the available millimeter and submillimeter observations of ND2H.
Domaines
Astrophysique [astro-ph]Origine | Fichiers produits par l'(les) auteur(s) |
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