Chemical reactions can be modelled via diffusion processes conditioned to
make a transition between specified molecular configurations representing the
state of the system before and after the chemical reaction. In particular the
model of Brownian dynamics - gradient flow subject to additive noise - is
frequently used. If the chemical reaction is specified to take place on a given
time interval, then the most likely path taken by the system is a minimizer of
the Onsager-Machlup functional. The Gamma limit of this functional is
determined in the case where the temperature is small and the transition time
scales as the inverse temperatur