Differential Cross-Sections for the Vibrationally Excited H + HOD(vOH = 1-4) → H2 + OD Reactions.

Abstract

Using the time-dependent wave-packet approach, we calculate the first fully converged state-to-state differential cross-sections for the H + HOD(vOH = 1-4) → H2 + OD reactions on a highly accurate neural network PES. It is found that, unlike the loss of memory effect observed in the product distributions for low vibrational excitation reactions, high initial OH vibrational excitation significantly influences not only the product vibrational distribution but also the angular distribution. Furthermore, for the H + HOD(vOH = 3,4) reactions, the total integral cross-sections maintain the pronounced oscillatory structures in the J = 0 probabilities at low collision energies, which originate from the prereactive van der Waals resonances. Notably, the product angular distributions exhibit forward-backward peaked behavior at these energies, akin to those observed in the complex-forming system with deep potential wells. This is attributed to the much longer lifetimes of these resonances compared to those of conventional transition state resonances.