  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.
