Vibrational relaxation of pure liquid water

Multicolor infrared ultrafast spectroscopy is applied to investigate the vibrational relaxation dynamics in liquid water at room temperature. In a sequence of experiments, both the stretching and the bending mode are photoexcited and probed. A unified model, capable of the reproduction of as much as 150 transients, yielded cross-sections and relaxation times for the stretching and bending modes. It is further demonstrated, that the energy from the initially excited stretching vibration is partitioned to the bending modes of approximately two water molecules.