Reactive scattering of alkali dimers. Alkali atom-dimer exchange reactions

Abstract

Reactive scattering measurements for the alkali atom-dimer exchange reactions M′+ M₂→ MM′+ M are reported, where M′= Na, K and M₂= Cs₂, Rb₂, K₂. The total reaction cross sections are large [graphic omitted] 100 Ų, indicating that a major fraction of collisions, captured by the long range van der Waals attraction, lead to reaction. Very little (∼10 %) of the available energy is disposed into product translation, consequently the MM′ dimer products are highly vibrationally excited (∼75 % of the MM′ bond energy). Only an indication of the centre-of-mass differential reaction cross sections can be deduced from the data. Calculations of the reaction potential energy surfaces show a broad shallow basin at small internuclear distances, and suggest that the reaction dynamics must be direct or at most involve a short-lived complex.