We propagate the dynamics using MCTDH with six active modals for each mode and as an initial wave function we use the full vibrational configuration interaction (FVCI) wave function obtained from the reference three-mode PES and using the six lowest-energy VSCF modals from each mode as the basis. We will propagate the wave function through a simulation time of 2.0•10 5 a.u. (4.838 ps) and similar to the ammonia double well system, we will initialize the dynamics by simulating a short laser pulse. We will thus add a time-dependent perturbation to the system according to Eqs. 53 and 54. We will still only consider a perturbation directly in one displacement coordinate and we choose to use the symmetric bend