title: The Role of excited-state topology in three-body dissociation of sym-triazine.
abstract: Molecular fragmentation into three products poses an analytical challenge to theory and experiment alike. We used translational spectroscopy and high-level ab initio calculations to explore the highly debated three-body dissociation of sym-triazine to three hydrogen cyanide molecules. Dissociation was induced by charge exchange between the sym-triazine radical cation and cesium. Calculated state energies and electronic couplings suggest that reduction initially produces a population of sym-triazine partitioned between the 3s Rydberg and pi* <-- n electronically excited manifolds. Analysis of the topology of these manifolds, along with momentum correlation in the dissociation products, suggests that a conical intersection of two potential energy surfaces in the 3s Rydberg manifold leads to stepwise dissociation, whereas a four-fold glancing intersection in the pi* <-- n manifold leads to a symmetric concerted reaction.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: John D
authors.initials: JD
authors.lastname: Savee
authors.forename: Vadim A
authors.initials: VA
authors.lastname: Mozhayskiy
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Mann
authors.forename: Anna I
authors.initials: AI
authors.lastname: Krylov
authors.forename: Robert E
authors.initials: RE
authors.lastname: Continetti