  Rabi oscillations have long been thought to be out of reach in simulations
using time-dependent density functional theory (TDDFT), a prominent symptom of
the failure of the adiabatic approximation for non-perturbative dynamics. We
present a reformulation of TDDFT which requires response quantities only, thus
enabling an adiabatic approximation to predict such dynamics accurately because
the functional is evaluated on a density close to the ground-state, instead of
on the fully non-perturbative density. Our reformulation applies to it any
real-time dynamics, redeeming TDDFT far from equilibrium. Examples of a
resonantly-driven local excitation in a model He atom, and charge-transfer in
the LiCN molecule are given.
