to represent ground and excited vibrational states associated with the left well (reactant) and the right well (product), which are depicted in Fig, . In this picture, the vibrational frequency ω 0 for the reactant is defined as the transition frequency associated with |ν L ⟩ → |ν ′ L ⟩, see Methods, Eqs. 26-28 for details. The description of Ĥν and Ĥloss are provided in Methods, Eqs. 29-31. The rest of the details for the model are provided in Supplementary Note 1.