Contributions from the atom less than M mass is considered as the faster time scaled motions than those from the atom more than M mass. See the more details about this in J. Phys. See the more details about these lengths in J. Phys. But in gener there will be coupling between those motions, so this leads the limitation of time scales. In Multiple time scale, I and J are the number of cycle that you want to calculate short time scaled and medium time scaled motions, respectively, before calculating long time scaled motion.
Delta t is the integration time step of long time scaled motions.
Energy and forces from Urey-Bradely term is incoporated with bond command. MTS method is interacted with Nose-Hoover mothod. Followings are lists of possible selections. Scalar include fast and slow routine.