Temperature dependence of vibrational relaxation in liquid 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 $T_1$ increases from 260±18 fs at $\text{T=298}$ K to 320±18 fs at $\text{T=358}$ K. The increase in lifetime with temperature can be quantitatively explained from the decrease in overlap resonance between the OH-stretch vibration and the overtone of the H–O–H bending mode.