Quantum tunneling during interstellar surface-catalyzed formation of water: the reaction H + H₂O₂ → H₂O + OH.

ABSTRACT: The final step of the water formation network on interstellar grain surfaces starting from the H + O₂ route is the reaction between H and H₂O₂. This reaction is known to have a high activation energy and therefore at low temperatures it can only proceed via tunneling. To date, however, no rate constants are available at temperatures below 200 K. In this work, we use instanton theory to compute rate constants for the title reaction with and without isotopic substitutions down to temperatures of 50 K. The calculations are based on density functional theory, with additional benchmarks for the activation energy using unrestricted single-reference and multireference coupled-cluster single-point energies. Gas-phase bimolecular rate constants are calculated and co

SUBMITTER: Lamberts T 

PROVIDER: S-EPMC5317215 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature