| The low-lying conical intersections between the lowest two electronic states of two radicals, vinoxy and ethoxy, are characterized; the minima on the crossing seams are located and the branching space is described through characteristic parameters. For vinoxy, the seam of conical intersection is characterized and fully described in the vicinity of the hydrogen dissociation reaction pathway. In ethoxy, vibronic coupling is very important owing to the very low position of its crossing seam relative to the overall potential minimum. For ethoxy, a second order Hamiltonian is used to describe both the branching space and the seam space in the vicinity of the minimum on the crossing seam. That Hamiltonian, which includes relativistic corrections, is then used to simulate the photoelectron spectrum of ethoxy. |
