where we introduced here, for every trajectory α and for every nucleus ν, the concepts of velocity, i.e., Ṙα ν (t), of momentum, i.e., P α ν (t), and of force, i.e., F α ν (t). In particular, P α ν (t) and F α ν (t) are expressed in terms of the TDVP and of the TDPES.