Dissociative electron attachment to the H2O molecule. II. Nuclear dynamics on coupled electronic surfaces within the local complex potential model

TL;DR

This study uses advanced nuclear dynamics calculations within a complex potential model to analyze dissociative electron attachment to water, considering multiple electronic states and their couplings, providing insights into major fragmentation channels.

Contribution

First-principles multidimensional nuclear dynamics calculations incorporating electronic state couplings for dissociative electron attachment to H2O.

Findings

Qualitative agreement with major fragment channels

Partial success in reproducing minor channels

Assessment of local complex potential model applicability

Abstract

We report the results of a first-principles study of dissociative electron attachment to H2O. The cross sections are obtained from nuclear dynamics calculations carried out in full dimensionality within the local complex potential model by using the multi-configuration time-dependent Hartree method. The calculations employ our previously obtained global, complex-valued, potential-energy surfaces for the three (doublet B1, doublet A1, and doublet B2) electronic Feshbach resonances involved in this process. These three metastable states of H2O- undergo several degeneracies, and we incorporate both the Renner-Teller coupling between the B1 and A1 states as well as the conical intersection between the A1 and B2 states into our treatment. The nuclear dynamics are inherently multidimensional and involve branching between different final product arrangements as well as extensive excitation of the diatomic fragment. Our results successfully mirror the qualitative features of the major fragment channels observed, but are less successful in reproducing the available results for some of the minor channels. We comment on the applicability of the local complex potential model to such a complicated resonant system.