Title | Zero-point energy, tunnelling, and vibrational adiabaticity in the Mu + H-2 reaction |
Publication Type | Journal Article |
Year of Publication | 2015 |
Authors | Mielke, SL, Garrett, BC, Fleming, DG, Truhlar, DG |
Journal | MOLECULAR PHYSICS |
Volume | 113 |
Pagination | 160-175 |
Date Published | JAN 17 |
ISSN | 0026-8976 |
Abstract | Isotopic substitution of muonium for hydrogen provides an unparalleled opportunity to deepen our understanding of quantum mass effects on chemical reactions. A recent topical review in this journal of the thermal and vibrationally state-selected reaction of Mu with H-2 raises a number of issues that are addressed here. We show that some earlier quantum mechanical calculations of the Mu + H-2 reaction, which are highlighted in this review, and which have been used to benchmark approximate methods, are in error by as much as 19% in the low-temperature limit. We demonstrate that an approximate treatment of the Born-Oppenheimer diagonal correction that was used in some recent studies is not valid for treating the vibrationally state-selected reaction. We also discuss why vibrationally adiabatic potentials that neglect bend zero-point energy are not a useful analytical tool for understanding reaction rates, and why vibrationally non-adiabatic transitions cannot be understood by considering tunnelling through vibrationally adiabatic potentials. Finally, we present calculations on a hierarchical family of potential energy surfaces to assess the sensitivity of rate constants to the quality of the potential surface. |
DOI | 10.1080/00268976.2014.951416 |
