  Using the Dominant Reaction Pathways method, we perform an ab-initio
quantum-mechanical simulation of a conformational transition of a peptide
chain. The method we propose makes it possible to investigate the
out-of-equilibrium dynamics of these systems, without resorting to an empirical
representation of the molecular force field. It also allows to study rare
transitions involving rearrangements in the electronic structure. By comparing
the results of the ab-initio simulation with those obtained employing a
standard force field, we discuss its capability to describe the non-equilibrium
dynamics of conformational transitions.
