Rank-1 Saddle Transport in Three or More Degrees of Freedom Scattering Reactions

Abstract

A computationally effective method is developed to study rank-1 saddle transport. In particular, the lifetime distribution is calculated for the planar, nonzero angular momentum scattering reaction of H2 with H2O. The scattering model uses the approximate potential of Wiesenfeld et al.[14], which has 3 essential degrees of freedom (DOF) and a rotating transition state (TS) at physically relevant energies. A Monte Carlo sampling of the energy surface on a transverse cut near the TS provides a representative set of trajectories which are integrated forward and backward to test for reactivity. Reactive trajectories are then integrated forward into the bound state until they escape the reaction, resulting in orbit/collision data for each trajectory. This data is collected and binned until the standard deviation of the data in each bin is within a user defined tolerance, yielding a lifetime distribution with bounded error terms. To test this method, it is applied to the well studied phenomena of electron scattering in the Rydberg atom with crossed fields[1,4] and compared with the literature.