An additional option with respect to SchNarc is that during the generation or conversion of a data base, smooth NACs can be added to the data base. As previously described, the direct learning of NACs is a challenging ML task, since the overall shape of the couplings (including singularities and cusps) is difficult to fit. The way of smoothing these sharp features is by multiplying the coupling values between two states with the respective energy difference of these two states, which reads as