The reweighted ensemble Z ME 0 obtained in the first step, refines simulation results by integrating the information from experimental data. However, the information extracted from experiments is encapsulated within the weights {w i : i = 1, ..., N }, which are inherently system-specific and cannot be directly applied to other systems. To make the information obtained from one system's experimental data applicable to others, it is crucial to integrate this information into force fields. We achieve this integration by optimizing force field parameters, denoted as θ, to reproduce the reweighted ensemble Z ME 0 .