Low temperature HD + $ortho$-/$para$-H$_2$ inelastic scattering of astrophysical interest

TL;DR

This study computes state-selected cross sections and rate coefficients for HD + ortho-/para-H2 collisions at low temperatures using a modified H2-H2 potential, providing insights relevant to astrophysical environments.

Contribution

It introduces new quantum-mechanical calculations of HD + H2 inelastic scattering using a modified potential energy surface, comparing results with previous models.

Findings

New cross sections and rate coefficients at low temperatures

Comparison shows differences with older PES-based calculations

Results are relevant for modeling astrophysical molecular clouds

Abstract

State-selected total cross sections and thermal rate coefficients are computed for the HD + $ortho$-/$para$-H$_2$ rotational energy transfer collision at low temperatures: 2 K $\lesssim$ T $\lesssim$ 300 K. A modified H$_2$-H$_2$ potential energy surface (PES) devised by Hinde is used for this pure quantum-mechanical dynamical computation. A comparison of the new results for the HD + $ortho$-/$para$-H$_2$ scattering problem and previous calculations computed with the use of other older PESs is presented and discussed.