Fig. 2. (A) Force-modified activation energy of the conrotatory ring-opening reactions of trans-dipropyl aziridine. The grey line marks 0 kcal mol⁻¹, i.e. where the potential activation barrier vanishes, the dashed black line marks the rupture force F_R, the magnitude of force where this occurs. The structure inlay shows the setup of the external pulling force applied during computations. Terminal carbon atoms to which the force is applied are marked in green. (B) Potential energies along the intrinsic reaction coordinates (IRCs) of the reaction, at integer values of external force up to F_R (0.0 nN to 6.0 nN). Increasing force is displayed in darker blue. Round markers denote the transition state structure, corresponding to the activation energies in (A). The grey line marks 0 kcal mol⁻¹.