Isotopic Hydrogen-Ion—Molecule Reactions

Abstract

The reactions of isotopic hydrogen‐molecule ions with isotopic hydrogen molecules have been investigated using a mass spectrometer ion source as the reaction chamber. No significant differences were detected in a study of the velocity distributions of the product and reactant ions. Rate constants for the formation of H₃⁺, D₃⁺, and H₂D⁺+D₂H⁺ were obtained from the reactions of H₂⁺–H₂, D₂⁺—D₂, and HD⁺—HD, respectively, which were in excellent agreement with theory. Isotopic fractionation was observed in the production of H₂D⁺ and D₂H⁺ from mixtures of H₂ and D₂, HD and H₂, HD and D₂. The isotope effects are qualitatively consistent with a more rapid formation of lower zero‐point energy intermediates.