FRESH Lecture: Probing the surface of ice with nonlinear vibrational spectroscopy
- Thursday 5 March 2020
- Gorlaeus Building
2333 CC Leiden
We studied the molecular-scale properties of the surface of ice with heterodyne-detected surface sum-frequency generation (HD-SFG) using femtosecond mid-infrared light pulses. This technique measures the vibrational spectrum of molecules at interfaces with a probing depth of only a few molecular layers.
We find that the vibrational spectrum of the top molecular layers of an ice crystal strongly resembles the surface vibrational spectrum of liquid water, even at ~30 degrees below the melting point. This liquid-like layer is also observed when the ice surface is covered with a protein layer. An exception is the hyperactive anti-freeze protein RmAFP of the beetle Rhagium Mordax. We will discuss the relation between the effect of RmAFP on the top molecular layers of ice and its antifreeze working mechanism.
- W.J. Smit and H.J. Bakker, Angew. Chem. Int. Ed. 56, 15540 (2017).
- K. Meister et al. J. Chem. Phys. Comm. 150, 131101 (2019).