Accurate Determination of Tunneling-Affected Rate Coefficients: Theory Assessing Experiment

5 years ago

Accurate Determination of Tunneling-Affected Rate Coefficients: Theory Assessing Experiment

Daiqian Xie, Junxiang Zuo, Hua Guo, Changjian Xie

The thermal rate coefficients of a prototypical bimolecular reaction are determined on an accurate ab initio potential energy surface (PES) using ring polymer molecular dynamics (RPMD). It is shown that quantum effects such as tunneling and zero-point energy (ZPE) are of critical importance for the HCl + OH reaction at low temperatures, while the heavier deuterium substitution renders tunneling less facile in the DCl + OH reaction. The calculated RPMD rate coefficients are in excellent agreement with experimental data for the HCl + OH reaction in the entire temperature range of 200–1000 K, confirming the accuracy of the PES. On the other hand, the RPMD rate coefficients for the DCl + OH reaction agree with some, but not all, experimental values. The self-consistency of the theoretical results thus allows a quality assessment of the experimental data.

Publisher URL: http://dx.doi.org/10.1021/acs.jpclett.7b01296

DOI: 10.1021/acs.jpclett.7b01296