The Role of excited-state topology in three-body dissociation of sym-triazine.
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.
Savee
John D
JD
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA.
Mozhayskiy
Vadim A
VA
Mann
Jennifer E
JE
Krylov
Anna I
AI
Continetti
Robert E
RE