  An application of impedance measurement technique (IMT) for a detection of
quantum tunneling in molecular structures is investigated. A charged particle
which tunnels in a two-well potential is electrically coupled to a high-quality
superconducting LC-circuit(tank) that makes possible a measurement of the
electric susceptibility of the molecule at the resonant frequency of the tank.
The real part of this susceptibility bears information about the tunneling rate
through a measurable parameter - a phase angle between the tank voltage and a
bias current applied to the tank. It is shown that the present approach is
highly sensitive and allows the monitoring of the tunnel motion of charged
nuclei in a single molecule.
