Eur. Phys. J. D (2016) 70: 48
https://doi.org/10.1140/epjd/e2016-60733-5

Regular Article

The HO₂ + (H₂O)_n + O₃ reaction: an overview and recent developments^*,**

Centro de Química and Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal

^a e-mail: lpviegas@ci.uc.pt
^b e-mail: varandas@uc.pt

Received: 28 December 2015
Published online: 3 March 2016

Abstract

The present work is concerned with the reaction of the hydroperoxyl radical with ozone, which is key in the atmosphere. We first give a brief overview which emphasizes theoretical work developed at the authors’ Group, considering not only the naked reaction (n = 0) but also the reaction with one water molecule added to the reactants (n = 1). Aiming at a broad and contextual understanding of the role of water, we have also very recently published the results of the investigation considering the addition of water dimers (n = 2) and trimers (n = 3) to the reactants. Such results are also succinctly addressed before we present our latest and unpublished research endeavors. These consist of two items: the first one addresses a new mechanistic pathway for hydrogen-abstraction in n = 2–4 cases, in which we observe a Grotthuss-like hydrogen shuttling mechanism that interconverts covalent and hydrogen bonds (water molecules are no longer spectators); the second addresses our exploratory calculations of the HO₂ + O₃ reaction inside a (H₂O)₂₀ water cage, where we strive to give a detailed insight of the molecular processes behind the uptake of gas-phase molecules by a water droplet.