Ultrafast dynamics of liquid water

Summary form only given. Using THz-time domain spectroscopy, we have studied the dynamics of pure water in the far-infrared spectral range, where the diffusive and inertial rotational motion of the water molecules is observed. With femtosecond transient absorption spectroscopy we have studied the relaxation (vibration, solvation, thermalization, and translation) of different solutes in liquid water. The solutes include, the hydrated electron, ClO/sub 2/, ClOH, Cl, and CS/sub 2/. Performing the femtosecond experiments at different temperatures gives insight into the connection between the dynamics observed in the far-infrared and the relaxation dynamics of the different solutes. In addition we also discuss the validity of employing macroscopic parameters (diffusion coefficients and temperature) in the description of single molecule dynamics on an ultrashort time scale.