Document Type

Article

Publication Date

8-2024

Publisher

EDP Sciences

Source Publication

Astronomy & Astrophysics

Source ISSN

0004-6361

Original Item ID

DOI: 10.1051/0004-6361/202450738

Abstract

Aims. The goal is to develop a database of rate coefficients for rotational state-to-state transitions in H2O + H2O collisions that is suitable for the modeling of energy transfer in nonequilibrium conditions, in which the distribution of rotational states of H2O deviates from local thermodynamic equilibrium.

Methods. A two-temperature model was employed that assumed that although there is no equilibrium between all possible degrees of freedom in the system, the translational and rotational degrees of freedom can be expected to achieve their own equilibria independently, and that they can be approximately characterized by Boltzmann distributions at two different temperatures, Tkin and Trot.

Results. Upon introducing our new parameterization of the collisional rates, taking into account their dependence on both Tkin and Trot, we find a change of up to 20% in the H2O rotational level populations for both ortho and para-H2O for the part of the cometary coma where the nonequilibrium regime occurs.

Comments

Published version. Astronomy & Astrophysics, Vol. 688 (August 2024). DOI. © The Authors 2024. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Download
Babikov_16432acc.docx (1600 kB)
ADA Accessible Version

Included in

Chemistry Commons

Share

COinS