We report a femtosecond time-resolved study of water at the neat water-air interface. The O-H stretch vibrational lifetime of hydrogen-bonded interfacial water is measured using surface-specific 4th-order nonlinear optical spectroscopy with femtosecond infrared pulses. The vibrational lifetime in the frequency range of 3200 to 3500 cm-1 is found to closely resemble that of bulk water, indicating ultrafast exchange of vibrational energy between surface water molecules and those in the bulk.

doi.org/10.1103/physrevlett.98.098302
Phys. Rev. Lett.

Smits, M., Ghosh, A., Sterrer, M., Müller, M., & Bonn, M. (2007). Ultrafast vibrational energy transfer between surface and bulk water at the air-water interface. Phys.Rev.Lett., 98(Article number: 98302), 1–4. doi:10.1103/physrevlett.98.098302