Larger-scale motions solvent effects

BD simulation is similar to MD simulations [26]. However it introduees a few new approximations that allow one to perform simulations on the mieroseeond timescale whereas MD simulation is known up to a few nanoseeonds. In BD the explicit description of solvent molecules used in MD is replaced with an implicit continuum solvent description. Besides, the internal motions of molecules are typically ignored, allowing a much larger time step than that of MD. Therefore, BD is particularly useful for systems where there is a large gap of time scale governing the motion of different components. For example, in polymer-solvent mixture, a short time-step is required to resolve the fast motion of the solvent molecules, whereas the evolution of the slower modes of the system requires a larger time-step. However, if the detailed motion of the solvent molecules is concerned, they may be removed from the simulation and their effects on the polymer are represented by dissipative (-yP) and random (o C (0) force... 

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