  We present an information geometric analysis of off-resonance effects on
classes of exactly solvable generalized semi-classical Rabi systems.
Specifically, we consider population transfer performed by four distinct
off-resonant driving schemes specified by su(2; C) time-dependent Hamiltonian
models. For each scheme, we study the consequences of a departure from the
on-resonance condition in terms of both geodesic paths and geodesic speeds on
the corresponding manifold of transition probability vectors. In particular, we
analyze the robustness of each driving scheme against off-resonance effects.
Moreover, we report on a possible tradeoff between speed and robustness in the
driving schemes being investigated. Finally, we discuss the emergence of a
different relative ranking in terms of performance among the various driving
schemes when transitioning from on-resonant to off-resonant scenarios.
