Polarization effect on molecular ionization and Rydberg-state excitation in laser fields

We have studied the impact of the dynamic core-electron polarization on molecular ionization and Rydberg-state excitation for CO molecules subjected to different laser pulses by numerically solving the three-dimensional time-dependent Schrödinger equations (TDSE) and semiclassical simulations. It is found that the ionization and the Rydberg-state excitation prefer to occur for the peak electric field pointing from C nucleus to O nucleus if the multielectron polarization effect is included, which are consistent with previous experimental observations. In addition, the electron tends to occupy the low-lying excited states after the occurrence of tunneling and the excitation yield increases relatively with respect to the ionization probability if the polarization effect is considered, and the above intriguing features are ascribed to the facts that the tunneling exit becomes closer to the core due to the polarization effect.