The parameterization process of GAFF starts by assigning partial charges. In the early stages of GAFF, Hartree Fock (HF) with the 6-31G* basis set were used to generate electrostatic potentials from which restrained electrostatic potential (RESP) charge fits were derived. This process proved to be expensive, especially for large molecules and led to the development of the AM1-BCC charge scheme that approximate HF/6-31G* RESP computation by first calculating charges using the AM1 semi-empirical model and correct it via bond charge corrections. In GAFF, the equilibrium bond length θ eq are fitted through experimental data from X-ray and neutron diffraction, as well as MP2/6-31G* computations. On the other hand, bond angle parameterization uses reference from the Cambridge Structure Database, empirical rules and MP2/6-31G* computations. Finally, the strategy for developing torsional angle parameters involves performing torsional angle scanning and fitting the parameters to accurately reproduce the rotational profile obtained from MP2/6-31G* calculations. The vdW parameters are the same as those used by AMBER and thus extracted from a database.