Missing-rung problem in vibrational ladder climbing

Vibrational ladder climbing (VLC), which is a cascade excitation process of molecular vibrational levels under chirped laser pulses, one the promising methods to realize bond breaking, but there have been few experimental reports on breaking by VLC. In this study we observed vanishing transition dipole moment, interrupting VLC in general systems. This phenomenon, that adjacent forbidden at certain level, was found be explained parities function and wave functions. order preserve VLC, proposed method use an additional pulse realizes ``double-stepping'' transitions where are forbidden. To show effectiveness our method, conducted wave-packet dynamics simulations for LiH dissociations with pulses. The results indicate efficiency dissociation significantly improved compared conventional single pulse. We also revealed quantum interference effect behind relative phase between main has significant probabilities molecules.