A full-dimensional quantum dynamics study of the mode specificity in the H + HOD abstraction reaction

Abstract

We employ the initial state-selected time-dependent wave packet approach to an atom-triatom reaction to study the H + HOD → OH + HD/OD + H2 reaction without the centrifugal sudden approximation, based on an accurate potential energy surface which was recently developed by neural network fitting to high level ab initio energy points. The total reaction probabilities and integral cross sections, which are the exact coupled-channel results, are calculated for the HOD reactant initially in the ground and several vibrationally excited states, including the bending excited state, OD stretching excited states, OH stretching excited states, and combined excitations of them. The reactivity enhancements from different initial states of HOD are presented, which feature strong bond-selective effects of the reaction dynamics. The current results for the product branching ratios, reactivity enhancements, and relative cross sections are largely improved over the previous calculations, in quantitatively good agreement with experiment. The thermal rate constant for the title reaction and the contributions from individual vibrational states of HOD are also obtained.

A local mode picture for H atom reaction with vibrationally excited H2O: a full dimensional state-to-state quantum dynamics investigation

“…Recently, Fu et al calculated the exact coupled-channel (CC) integral cross sections (ICSs) for H 2 O and HOD initially in the first and second stretching excited states and simultaneous excitations of both bending and stretching modes on the YZCL2 PES, and observed strong mode specific and bond selected reactivity as discovered in the experiments. 24,25 …”

The “bound wavefunction” on the repulsive excited () state of the HD+ molecule

“…of the function and the destructive interference near the boundaries of the function. Moreover, comparing the peak values of Figures B and B,D, we also note that with the increase of the quantum number v , the amplitude of the component on the excited state, , increases.…”

“…The formations of the initial wavefunctions are important in many aspects of molecular dynamics, such as the photodissociation, high‐order harmonic generation, molecular collision reaction, and so forth (see e.g., Refs. [ ]). The above threshold dissociation of the HD + molecule starting from vibrational levels v = 0 and v = 10 indicated that the change of the initial wavefunction has a dramatic influence on dissociation channels .…”

Differential Cross Sections for the H+D2O→HD+OD Reaction: a Full Dimensional State-to-State Quantum Dynamics Study

“…Theoretically, besides the quasiclassical trajectory (QCT) studies of Schatz et al [12−14] there have been a number of quantum dynamics studies [15−19], which are in qualitative agreement with the experimental observations. Recently, Fu et al calculated the exact coupled-channel (CC) integral cross sections (ICS) for H 2 O and HOD initially in the first and second stretching excited states and simultaneous excitations of both bending and stretching modes on the YZCL2 PES, and observed strong mode specific and bond selected reactivity as discovered in the experiments [20,21].…”