Vibrational fine structures revealed by the real-time vibrational phase and amplitude in MEH-PPV using few cycle pulses

Abstract

It was found that the vibronic transition peaks hidden in a featureless spectrum of induced absorption could be clearly revealed by utilizing the spectra of phases and amplitudes of the molecular vibrational modes. Some of the peaks were also found in a second derivative of a transition spectrum integrated over a delay time from 100 to 700 fs. This is because of the localization of a wave packet in a limited region along the potential multimode hypersurfaces. The transition energy of an induced absorption or an induced emission corresponds to some localized point (space) on the potential hypersurface to which the wave packets visit with some fixed phases.