The desire to better understand the quantum nature of isomerization led to recent experimental observations of the vibrationally induced isomerization of OC–NaCl(100) to CO–NaCl(100). To investigate the mechanism of this isomerization, we performed dynamics calculations using finite (CO–NaCl)n cluster models. We constructed new potential energy surfaces for CO–NaCl and CO–CO interactions using high-level ab initio data and report key properties of the bare CO–NaCl potential energy surface, which show much in common with the experiment. We investigated the isomerization dynamics using several cluster models and, in all cases, isomerization was seen for highly excited CO vibrational states, in agreement with experiments. A detailed examination of the reaction trajectories indicates that isomerization occurs when the distance between CO and NaCl is larger than the distance at the conventional isomerization saddle point, which is a strong indicator of ‘roaming’.
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The potentials reported in the paper are available in compressed folders as Supplementary Information.
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J.M.B. and H.G. thank the Alexander von Humboldt Foundation for Humboldt Research Awards. In addition, J.M.B. thanks NASA (80NSSC20K0360) for financial support and H.G. thanks the National Science Foundation (CHE-1462109 and CHE-1951328) for financial support. We thank J. Lau and A. Wodtke for extensive discussions.
The authors declare no competing interests.
Peer review information Nature Chemistry thanks Jochen Vogt and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
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Supplementary Figs. 1–14, and Tables 1–9.
QCT Trajectory Animation.
All three PES Software. ‘CO_CO_Int’ folder contains CO-CO interaction PES; ‘CO_MRCI’ folder contains isolated CO PES; and ‘NaCl_CO_Int’ folder contains NaCl-CO interaction PES.
Source data for the figures within the Supplementary Information file.
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Nandi, A., Zhang, P., Chen, J. et al. Quasiclassical simulations based on cluster models reveal vibration-facilitated roaming in the isomerization of CO adsorbed on NaCl. Nat. Chem. (2021). https://doi.org/10.1038/s41557-020-00612-y