Molecular Ro-vibrational Collision Rates for Infrared Modeling of Warm Interstellar Gas from Full-dimensional Quantum Calculations

Metadata Updated: February 28, 2019

We propose to compute accurate collisional excitation rate coefficients for rovibrational transitions of CS, SiO, SO, NO, H_2O, and HCN due to H_2, He, or H impact. This extends our previous grant which focused on 3- and 4-atom systems to 4- and 5-atom collision complexes, with dynamics to be performed on 6-9 dimensional potential energy surfaces (PESs). This work, which uses fully quantum mechanical methods for inelastic scattering and incorporates full-dimensional PESs, pushes beyond the state-of-the-art for such calculations, as recently established by our group for rovibrational transitions in CO-H_2 in 6D. Many of the required PESs will be computed as part of this project using ab initio theory and basis sets of the highest level feasible and particular attention will be given to the long range form of the PESs. The completion of the project will result in 6 new global PESs and state-to-state rate coefficients for a large range of initial rovibrational levels for temperatures between 1 and 3000 K. The chosen collision systems correspond to cases where data are limited or lacking, are important coolants or diagnostics, and result in observable emission features in the infrared (IR). The final project results will be important for the analysis of a variety of interstellar and extragalactic environments in which the local conditions of gas density, radiation field, and/or shocks drive the level populations out of equilibrium. In such cases, collisional excitation data are critical to the accurate prediction and interpretation of observed molecular IR emission lines in protoplanetary disks, star-forming regions, planetary nebulae, embedded protostars, photodissociation regions, etc. The use of the proposed collisional excitation data will lead to deeper examination and understanding of the properties of many astrophysical environments, hence elevating the scientific return from the upcoming JWST, as well as from current (SOFIA, Herschel, HST) and past IR missions (Spitzer, ISO), and from ground-based telescopes.

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Public: This dataset is intended for public access and use. License: U.S. Government Work

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Metadata Created Date February 28, 2019
Metadata Updated Date February 28, 2019

Metadata Source

Harvested from NASA Data.json

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Resource Type Dataset
Metadata Created Date February 28, 2019
Metadata Updated Date February 28, 2019
Publisher Space Technology Mission Directorate
Unique Identifier TECHPORT_72012
Maintainer Email
Public Access Level public
Bureau Code 026:00
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Schema Version
Catalog Describedby
Harvest Object Id f8c6fd93-a82b-42d4-83c4-3e04460a9666
Harvest Source Id 39e4ad2a-47ca-4507-8258-852babd0fd99
Harvest Source Title NASA Data.json
Data First Published 2020-01-01
Homepage URL
Data Last Modified 2018-09-07
Program Code 026:027
Source Datajson Identifier True
Source Hash 5fbec1f639f94d15f996d6c4f617c9d53f3b91ca
Source Schema Version 1.1

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