Here, we provide two examples of fitting diffusion coefficient and IR spectrum, which are the cases in paper Refining Potential Energy Surface through Dynamical Properties via
Differentiable Molecular Simulation. The core code of implementing the adjoint method is in the difftraj.py, which is also the DiffTraj module in DMFF.
The trained potential energy surface (EANN model) and dipole surface (Deep Dipole model) is provided as params_eann4.pickle and dipole.pb in IR-fitting folder.