Hydrogen bond dynamics of interfacial water molecules revealed from two-dimensional vibrational sum-frequency generation spectroscopy

Vibrational sum-frequency generation (vSFG) spectroscopy allows the study of the structure and dynamics of interfacial systems. In the present work, we provide a simple recipe, based on a narrowband IR pump and broadband vSFG probe technique, to computationally obtain the two-dimensional vSFG spectrum of water molecules at the air-water interface. Using this technique, to study the time-dependent spectral evolution of hydrogen-bonded and free water molecules, we demonstrate that at the interface, the vibrational spectral dynamics of the free OH bond is faster than that of the bonded OH mode.

Automated summary

In this study, a simple recipe based on narrowband IR pump and broadband vSFG probe technique was used to computationally obtain the two-dimensional vSFG spectrum of water molecules at the air-water interface. The study demonstrated that the vibrational spectral dynamics of the free OH bond is faster than that of the bonded OH mode at the interface.