Vibrational energy relaxation in H2O

We have determined the lifetime of the OH-stretch vibration in pure liquid water as a function of temperature using femtosecond mid-infrared pump-probe spectroscopy. The lifetime T1 increases from 260 ± 18 fs at T = 298 K to 320 ± 18 fs at T = 358 K. The increase in lifetime with temperature can quantitatively be explained from the decrease in spectral overlap of the OH-stretch vibration and the overtone of the H-O-H bending mode.