  We study numerically the behavior of RNA secondary structures under influence
of a varying external force. This allows to measure the work $W$ during the
resulting fast unfolding and refolding processes. Here, we investigate a
medium-size hairpin structure. Using a sophisticated large-deviation algorithm,
we are able to measure work distributions with high precision down to
probabilities as small as $10^{-46}$. Due to this precision and by comparison
with exact free-energy calculations we are able to verify the theorems of
Crooks and Jarzynski. Furthermore, we analyze force-extension curves and the
configurations of the secondary structures during unfolding and refolding for
typical equilibrium processes and non-equilibrium processes, conditioned to
selected values of the measured work $W$, typical and rare ones. We find that
the non-equilibrium processes where the work values are close to those which
are most relevant for applying Crooks and Jarzynski theorems, respectively, are
most and quite similar to the equilibrium processes. Thus, a similarity of
equilibrium and non-equilibrium behavior with respect to a mere scalar
variable, which occurs with a very small probability but can be generated in a
controlled but non-targeted way, is related to a high similarity for the set of
configurations sampled along the full dynamical trajectory.
