MD is virtually used for any atomic or molecular system. A set of N classical particles characterized by coordinates, velocities, and masses is selected. The forces acting on the particles are evaluated from the derivatives of the potentials, usually interacting through the sum of suitable pairs in most investigations. The equations of motion are solved numerically by standard methods. The statistical averages of interest are figured out by the positions and the velocities of the particles as time averages over the trajectories of the system in its phase space