*3.2.1.3 Force fields*

The set of parameters acting on the nuclei of atoms by which the potential energy (U) of a system is calculated of a molecular system is called Force fields. To find a correct force field is a challenging task in every simulation for a given system. Condensed-phase Optimized Molecular Potentials for Atomistic Simulation Studies (COMPASS) is the general force fields used for corrosion inhibition studies. In addition to ab initio calculations, COMPASS was parameterized considering various experimental data including organic compounds made with H, C, N, O, S, and P atoms, halogens, and metals. Universal force field (UFF) [141, 142], is an all-atom

potential containing parameters for each atom, and the consistent-valence force field (CVFF) t is a generalized valence force field that allow treating of organic molecules as well as metals [143–145].
