Rate coefficients for H₂:H₂ inelastic collisions in the ground vibrational state from 10 to 1000 K^★

¹ Instituto de Física Fundamental, CSIC (IFF-CSIC), C/ Serrano 123, 28006 Madrid, Spain
e-mail: marta@iff.csic.es
² Laboratory of Molecular Fluid Dynamics, Instituto de Estructura de la Materia, CSIC (IEM-CSIC), C/ Serrano 121, 28006 Madrid, Spain
e-mail: emsalvador@iem.cfmac.csic.es

Received: 29 October 2020
Accepted: 25 January 2021

Abstract

Aims. In this work, we present a pruned set of state-to-state rate coefficients (STS rates) for inelastic H₂:H₂ collisions in the thermal range from 10 to 1000 K. The set includes all relevant rates needed for diagnostics based on the simulation of quadrupole infrared spectra of H₂.

Methods. The reported set was obtained from a quantum scattering close-coupling calculation employing a recent version of the MOLSCAT code, a high-level potential energy surface, and rotational energies of the H₂ molecules with spectroscopic accuracy. These improvements have led to a significant increase in the accuracy with respect to previous computational results. The accuracy of the present STS rates is tested against recently reported experimental rates. Most dominant rates agree with the experiment within a 2σ uncertainty (2 to 6%).

Results. In addition to the tables given in the main text, three machine-readable tables are available at the CDS. These tables include all the relevant numerical results of the paper, namely, the excitation and de-excitation STS rates for H₂:H₂ inelastic collisions at selected temperatures between 10 and 1000 K, and their functional description for interpolation at any intermediate temperature.