title: Conical for stepwise, glancing for concerted: the role of the excited-state topology in the three-body dissociation of sym-triazine.
abstract: The highly debated three-body dissociation of sym-triazine to three HCN products has been investigated by translational spectroscopy and high-level ab initio calculations. Dissociation was induced by charge exchange between the sym-triazine radical cation and cesium. Calculated state energies and electronic couplings suggest that sym-triazine is produced in the 3s Rydberg and pi* <-- n manifolds. Analysis of the topology of these manifolds along with momentum correlation in the dissociation products suggest that the 3s Rydberg manifold characterized by a conical intersection of two potential energy surfaces leads to stepwise dissociation, while the pi* <-- n manifold consisting of a four-fold glancing intersection leads to a symmetric concerted reaction.
authors.affiliation: Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, USA.
authors.forename: Vadim A
authors.initials: VA
authors.lastname: Mozhayskiy
authors.forename: John D
authors.initials: JD
authors.lastname: Savee
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Mann
authors.forename: Robert E
authors.initials: RE
authors.lastname: Continetti
authors.forename: Anna I
authors.initials: AI
authors.lastname: Krylov