A secondary barrier to using synthetic data for transferable HAIEFF force-field parameterization is the absence of an appropriate tool for this purpose. Despite some of the parameterization attempts listed above, recent parameter estimation methodologies developed for HAIEFF models in the literature are computationally costly and limit the number of structures or parameters that can be optimised simultaneously . This means that a sequential optimisation scheme must be used, where each parameter is optimised individually or as part of a small set, while the other parameters are fixed.