effort, but in this way we ensure that no interaction is present in the reactant and product asymptotes. The propagation step is 0.1 fs to ensure that the energy and angular moment are conserved along each trajectory. At 298 K we ran 100 000 trajectories, where the CN radical rotational and vibrational quantum numbers were fixed at the ground-state. The ethane vibrational and rotational energies were selected by thermal sampling to reproduce the 298 K thermal distribution, and the relative translational energy of the reactants was obtained from the E/(RT) 2 exp(-E/RT) distribution. The remaining initial conditions (impact parameter, spatial orientation and vibrational phases) were selected from a Monte Carlo sampling. The maximum impact parameter, bmax= 6.5 Å was determined using small batches of trajectories, until no reactive trajectories were found. Given the large number of trajectories run, the statistical error is small or negligible (< 2%), and so they are not shown in the results. QCT calculations have a classical nature and so some trajectories end with vibrational energy below their zero-point energy (ZPE). This issue is commonly known as the ZPE violation problem. In the present paper we contemplated two approaches: considering all reactive trajectories in the final analysis (All approach)