Exact-Factorization Framework for Electron–Nuclear Dynamics in Electromagnetic Fields

397). From an intuitive argument that the atom must not be deflected by the Lorentz force from a straight line trajectory, it has been conjectured that the same compensation should occur within the EF theory as well. We prove that this property persists within the exact nonadiabatic theory, provided the atom is in its eigenstate. The latter finds itself in the conspicuous variance with the corresponding BO result, where the compensation holds for an arbitrary nuclear wave packet on a single BO potential surface.