Shape resonance in the H + D2O → D + HOD reaction: a full-dimensional quantum dynamics study

Abstract

We present exact coupled-channel (CC) results of full-dimensional quantum mechanical calculations for the H + D₂O → D + HOD exchange reaction which provide the first evidence for a shape resonance in this reaction, employing the initial state-selected time-dependent wave packet method with both OD bonds in the D₂O reactant treated as reactive bonds. Due to the shallow C_3v minimum along the reaction path, the signature of shape resonance is manifested as the existence of a distinct step-like feature in the CC integral cross sections of the exchange reaction just above the threshold. Our study also shows that the current CC integral cross sections are in very good agreement with the experimental results, and a bit larger than those calculated in the previous quantum dynamics study, where the one reactive bond and centrifugal sudden (CS) approximations were invoked, revealing that the one reactive bond approximation overestimated, while the CS approximation underestimated the integral cross sections.