title: Lepetit and Jackson reply:.
authors.affiliation: Université de Toulouse, UPS, Laboratoire Collisions Agrégats Réactivité, IRSAMC, F-31062 Toulouse, France and CNRS, UMR 5589, F-31062 Toulouse, France.
authors.forename: B
authors.initials: B
authors.lastname: Lepetit
authors.affiliation: Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA.
authors.forename: B
authors.initials: B
authors.lastname: Jackson