To dictate the photoactive motion displayed by this MM we define two potential states of the system. This uses the dihedral potential between the particles A-B-C-D and A'-B-C-D' noted in Eqn. 4. This potential has the parameter 𝑑, which is set as 1 or -1. This can be changed during the simulation to produce two distinct potential states as demonstrated in Fig. . These potential states have a minimum at either 0° or 180°, which effectively switches the stable configuration of particles A and A' to opposite sides of the molecule. Sequentially switching the potential parameter 𝑑 during the simulation, after a set number of time steps, a stepwise periodic rotation is achieved. This stepwise rotation is comparable to the type of motion observed in the experimental system. The motion between the two states occurs over a few simulation steps, which is comparable to the ultrafast dynamics reported for the excited-state photoisomerization rotation found in the experimental system. Throughout this study, the switching period, between the two potentials, was chosen as 50 𝜏. Currently, molecular rotary motors exhibit MHz-scale rotational frequencies . If we consider the particles in this study to have similar size and characteristics to Argon, the rotation rate is approximately 4.6 GHz. This is currently faster than is observed for MMs but represents the potential for such systems, as with specific functionalisation these systems could in principle function in the GHz regime. 48 The simple switching of the dihedral potentials can effectively produce a rotation about the axes of the molecule. However, because the potential switch sets this structural configuration atop the symmetric maximum of the dihedral potential energy surface the system can equally relax (by rotation) in either direction. This results in the non-directional rotation of the motor as demonstrated in Fig. . Unidirectional motion is a sought-after characteristic of molecular rotors known to work in porous frameworks. However, as with biological motor systems, directionality is essential to perform mechanical tasks. Synthetically this is achieved by photo-responsive sterically overcrowded alkenes, which results in four distinct steps as outlined in Fig. . To achieve unidirectional rotation in our simulations we employ a torsional bias force, orientated in the direction of the axle, thus mimicking the influence of sterically crowded functionalisation. This use of applied torque avoids increasing complex descriptions of the dihedral potential energy surface. While large bias forces result in continued, and uncontrolled, rotation, subsequent to the potential switch event, a bias force of 30 𝜎/𝜖 results in singular and unidirectional rotation (Fig. ). Notably, the sign of this bias torque dictates the direction of rotation, either clockwise or counter clockwise allowing the control of directionality, similar to the experimental MM for which rotational directionality is dictated by the nature of the stereo centre adjacent to the double bond. 50 As detailed here, we have demonstrated that a six-particle system can produce a minimal description of a molecular motor for classical molecular dynamics simulations. Our model switches between two distinct dihedral potentials and when combined with a bias torque this results in unidirectional rotation. Importantly, the motion we observe is comparable to the ratchet-like rotation designed in many synthetic molecular motors. 51