THz absorption spectroscopy: probing the fast hydrogen bond dynamics around ions and proteins

We have used THz absorption spectroscopy as a tool to probe the collective hydration dynamics of ions and proteins. Whereas in bulk water, the hydrogen bonds break and reform every picosecond on average, in the vicinity of solutes like proteins, water molecules show a retardation of hydrogen bonds rearrangement dynamics. We report here THz absorption spectroscopic measurements of anions and ions as well as proteins and explain the underlying molecular mechanism of the collective hydration dynamics in these systems.