# Reactivity of hydrated hydroxide anion cluster OH(H$_{2}$O)$_{n}^{-}$ with H and Rb: an ab initio study

## TL;DR

This study uses ab initio methods to analyze the structure, energetics, and detachment processes of hydrated hydroxide anion clusters and their complexes with H and Rb, providing insights into their reactivity relevant to astrochemistry and cold chemistry.

## Contribution

It offers a detailed theoretical characterization of hydrated hydroxide clusters and their collisional complexes, highlighting the importance of diffuse functions and exploring detachment pathways.

## Key findings

- Water loss and electronic detachment are key reaction channels.
- Diffuse functions are crucial for accurate potential energy surface description.
- Different detachment mechanisms depend on water loss timing.

## Abstract

We present a theoretical investigation of the hydrated hydroxide anion clusters OH(H$_{2}$O)$_{n}^{-}$ and of the collisional complexes H-OH(H$_{2}$O)$_{n}^{-}$ and Rb-OH(H$_{2}$O)$_{n}^{-}$ (with n$=1-4$). The MP2 and CCSD(T) methods are used to calculate interaction energies, optimized geometries and vertical detachment energies. Part of the potential energy surfaces are explored with a focus on the autodetachment region. We point out the importance of diffuse functions to correctly describe the latter. We use our results to discuss the different water loss and electronic detachment channels which are the main reaction routes at room temperature. In particular, we have considered a direct and an indirect process for the electronic detachment, depending on whether water loss follows or precedes the detachment of the excess electron. We use our results to discuss the implication for astrochemistry and hybrid trap experiments in the context of cold chemistry.