A dynamical ‘‘white spot’’ on the potential energy surface: The close interaction region of the collinear hydrogen transfer reaction F+DBr→FD+Br.

The strong FDBr interaction region located in the corner of the LEPS model potential energy surface is diagnosed as dynamical white spot. Although energetically accessible, it is dynamically unapproachable by the vast majority of reactive classical trajectories, quantum waves represented by S-matrix propagation, or resonance wave functions. The quantum and classical derivations and explanations yield important consequences of the dynamical white spot: In particular, quantum chemical evaluations of this region of the potential energy surface are rendered unneccessary because its dynamical effects on bi- and unimolecular reactivity are insignificant. [ABSTRACT FROM AUTHOR]