  We study the generation of electronic ring currents in the presence of
nonadiabatic coupling using circularly polarized light. For this, we introduce
a solvable model consisting of an electron and a nucleus rotating around a
common center and subject to their mutual Coulomb interaction. The simplicity
of the model brings to the forefront the non-trivial properties of electronic
ring currents in the presence of coupling to the nuclear coordinates and
enables the characterization of various limiting situations transparently.
Employing this model, we show that vibronic coupling effects play a crucial
role even when a single $E$ degenerate eigenstate of the system supports the
current. The maximum current of a degenerate eigenstate depends on the strength
of the nonadiabatic interactions. In the limit of large nuclear to electronic
masses, in which the Born-Oppenheimer approximation becomes exact, constant
ring currents and time-averaged oscillatory currents necessarily vanish.
