In the present case of pyrene, direct evaluation of the nonadiabatic coupling vector is not possible due to the chosen ADC(2) electronic structure theory, and we have carried out the velocity adjustment in the direction of the nuclear momentum at hoppings. Since pyrene is a relatively large polyatomic molecule (26 atoms) and prepared with high-energy initial conditions (trajectories are initiated from excited states as high as S8), there is always a considerable amount of kinetic energy available in the reservoir to facilitate the back hoppings. Consequently, surface hopping propagation with velocity adjustment in the momentum direction over-allows back hoppings, thus biasing the nuclear ensemble toward the excited states.