Collisions of Fe+ ions, clusters and hydroxides ligated by water molecules

Abstract

A laser evaporation source has been used to generate a beam of Fe ⁺ , FeOH ⁺ , Fe(OH) ₂ ⁺ , FeH ⁺ , Fe ₂ ⁺ and Fe ₃ ⁺ ions solvated by up to 11 water molecules, with the major series of ions corresponding to Fe(H ₂ O) _n ⁺ clusters. These ions were collided, prior to mass selection, with Ar, N ₂ , O ₂ or CH ₃ OH, and apparent scattering cross-sections were measured. Simple collision models, coupled with a Monte Carlo simulation of the scattering experiment, were used to account quantitatively for the observations. The most striking result is that only methanol exchanges with a cluster water molecule, although this is a minor channel. There is inelastic scattering with argon but the other collisions are mainly elastic.