Vibrational dynamics in liquids studied by non-linear infrared spectroscopy

Three-pulse photon echo experiments in the infrared region have been performed to study vibrational dephasing and transition frequency fluctuations in solutions. Time-integrated and frequency-resolved photon echo signals of the –N=C=N– anti-symmetric stretching mode of di-p-tolylcarbodiimide show an oscillatory behavior due to interference with a band nearby. Solvation dynamics or frequency fluctuations of several ions in hydrogen-bonding solvents have been studied and a couple of general trends of the time-correlation function of the frequency fluctuation on these systems have been observed.