High-order echoes in vibrational spectroscopy of liquids

Multidimensional infrared and Raman spectroscopy of liquids conducted using sequences of femtosecond pulses may be used to directly probe intramolecular and intermolecular nuclear motions. These techniques provide an additional insight into the nature of the nuclear spectral density observed in optical Kerr measurements. Photon echoes predicted in these systems are calculated and analyzed using multilevel coherences.