The Berendsen thermostat  is a method for controlling the temperature in a molecular dynamics simulation. The Berendsen thermostat uses a weak coupling to an external heat bath of temperature . This results in the modified equation of motion (Ref. 1 Eq. 8):
This represents a proportional scaling of the velocities per time step from to , where (Ref. 1 Eq. 11)
where is a time constant associated with the coupling.