Conical for stepwise, glancing for concerted: the role of the excited-state topology in the three-body dissociation of sym-triazine.
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.
Mozhayskiy
Vadim A
VA
Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, USA.
Savee
John D
JD
Mann
Jennifer E
JE
Continetti
Robert E
RE
Krylov
Anna I
AI