Reorientational and configurational fluctuations in water observed on molecular length scales

Abstract
Polarization-selective pump-probe and echo experiments on the OH vibration of HOD in D2O with 45femtosecond (fs) infrared pulses are analyzed self-consistently to reveal the time scales for vibrational relaxation, dephasing, and molecular reorientation. Librational motion and hydrogen bond fluctuations on 50- and 180fs time scales precede picosecond collective reorganization.