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.

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