Work

Cl+ and HCl+ in Reaction with H2 and Isotopologues: A Glance into H Abstraction and Indirect Exchange at Astrophysical Conditions

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Astrochemical models of interstellar clouds, the sites of stars, and planet formation require information about spin-state chemistry to allow quantitative comparison with spectroscopic observations. In particular, it is important to know if full scrambling or H abstraction (also known as proton hopping) takes place in ion-neutral reactions. The reaction of Cl + and HCl + with H 2 and isotopologues has been studied at cryogenic temperatures between 20 and 180 K using a 22 pole radio frequency ion trap. Isotopic exchange processes are used to probe the reaction mechanism of the HCl + + H 2 reaction. The results are compared with previous measurements and theoretical predictions. The rate coefficients for the Cl + + H 2 and HCl + + H 2 reactions are found to be constant in the range of temperatures studied, except for the DCl + + D 2 reaction, where a weak negative temperature dependence is observed, and reactions with D 2 are found to be significantly slower than the Langevin rate. No isotopic exchange reactions are observed to occur for the H 2 Cl + ion. The analysis of the products of the HCl + + H 2 isotopic system clearly indicates that the reaction proceeds via simple hydrogen atom abstraction.

Source: ACS Earth and Space Chemistry

DOI: 10.1021/acsearthspacechem.4c00414

Authors: Miguel Jiménez-Redondo, Olli Sipilä, Robin Dahl, Paola Caselli, Pavol Jusko

Institutions: Max Planck Institute for Extraterrestrial Physics, University of Bonn, RWTH Aachen University

Language: English

Topic: Astrophysics and Star Formation Studies

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500

Funder: Max-Planck-Gesellschaft