With a lower collision frequency of 0.02/ps, corresponding to weaker kicks and lower viscous drag, the thermostat has less influence on the dynamics, so the kinetic energy added to the system by downhill motion on the excited state PES and by the subsequent hop to the ground state led to larger and longer-lasting rises in the effective temperature (kinetic energy) of the motors. Presumably because of the more extreme temperature rises, we observed more replicates that completed both photoisomerization and THI during the QM simulations. Interestingly, setting the collision frequency to zero, which decouples the motor from any heat bath and leads to a constant energy simulation, caused the photoisomerization success rate to drop, and a number of replicates ended in numerical failure, presumably due to motions too fast for the selected time-step. With a higher collision frequency of 2/ps, the fraction of replicates that successfully hopped from the excited to the ground state within the simulation time was markedly reduced. Presumably, the increased viscosity slows rotation of the rotor toward the conical intersection, delaying return to the ground state.