  The realization of molecular-based electronic devices depends to a large
extent on the ability to mechanically stabilize the involved molecular bonds,
while making use of efficient resonant charge transport through the device.
Resonant charge transport can induce vibrational instability of molecular
bonds, leading to bond rupture under a bias voltage. In this work, we go beyond
the wide-band approximation in order to study the phenomenon of vibrational
instability in single molecule junctions and show that the energy-dependence of
realistic molecule-leads couplings affects the mechanical stability of the
junction. We show that the chemical bonds can be stabilized in the resonant
transport regime by increasing the bias voltage on the junction. This research
provides guidelines for the design of mechanically stable molecular devices
operating in the regime of resonant charge transport.
