On the complete ionization of a periodically perturbed quantum system
  We analyze the time evolution of a one-dimensional quantum system with zero range potential under time periodic parametric perturbation of arbitrary strength and frequency. We show that the projection of the wave function on the bound state vanishes, i.e. the system gets fully ionized, as time grows indefinitely. 
O. Costin, J. L. Lebowitz and A. Rokhlenko