Quantum beats and ultrafast solvation dynamics

The beats during solvation dynamics have been studied theoretically and experimentally, using the heterodyne optical Kerr effect and pump-probe spectroscopy. We showed that the solvation process increases the beat contrast due to the hole-burning effect. Owing to the dipole activity of the intramolecular vibration responsible for the beats, a dipole-dipole coupling between the intramolecular vibration and the solvation coordinate is available. We have calculated a correlation function of the perturbation of nuclear motion during electronic transition, when such a coupling exists. Taking into account the linkage between the intramolecular vibration and the solvation coordinate yields better agreement between theory and the experimental data. We have evaluated the value of the linkage. The evaluation conforms with the values obtained by the computer fit of the experimental signals. (C) 1999 American Institute of Physics. [S0021-9606(99)51337-8].