Merged beams at Minnesota

Abstract

A new merged-beam apparatus is described, which permits the measurement of the energy dependence of the absolute cross sections for ion–neutral and neutral–neutral reactions yielding ionic products over the energy range <0.010 to ∼10 eV. The apparatus has a somewhat different geometry than that of any previous merged-beam instrument and incorporates several innovations which facilitate the rapid measurement of relative cross sections, the accurate determination of the beam overlap integral, and the high-resolution measurement of the product energy distribution. The performance of the instrument is illustrated with data on the reaction H+2 + H2 → H+3 + H.