Associative detachment of rubidium hydroxide

Abstract

We performed calculations of the optimized structure, harmonic vibrational frequencies, and dissociation energies of RbOH and its anion, and investigate the interactions between Rb and OH${}^{\ensuremath{-}}$ leading to possible associative detachment pathways. The electron affinity of RbOH was computed to be 0.2890 eV, with a bond energy of Rb+OH${}^{\ensuremath{-}}$ half that of Rb+OH. To determine other possible charge loss pathways, the Rb+OH and Rb+OH${}^{\ensuremath{-}}$ dissociation curves were computed using coupled-cluster methods along all possible collisional angles. An adiabatic curve crossing between the neutral and charged molecule was found at the inner wall of the molecular potential curve for linear geometries. Associative detachment rates were estimated using the Langevin ion capture cross section for hydroxide. We find for $v\ensuremath{\ge}2$ an associative detachment rate of $>2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}$ cm${}^{3}$s${}^{\ensuremath{-}1}$, while for $v=0$ and 1 no appreciable rate exists. This strong dependence on vibrational level suggests the ability to control the associative detachment rate directly.