Born-Oppenheimer expansion: From muon distribution to dissipation in fission

It is shown that a consistent treatment of momentum translation by a muon in the problem of the distribution of muons among prompt-fission fragments modifies the nonadiabatic transition operator in the Born-Oppenheimer expansion and removes difficulties indicated in earlier calculations. The muon distribution for very asymmetric prompt fission proves to be highly sensitive to the velocity of the primary fragments at the scission point. The mean collective energy dissipated during saddle-to-scission descent due to the one-body mechanism is calculated within the same approach.