In a JPCB paper, we used molecular dynamics simulations to probe the relaxation dynamics and hydration structure in glycerol-water mixtures. The simulation results confirmed the physical picture revealed by the terahertz spectroscopic measurements from Nguyen's group. The results show the existence of a critical glycerol concentration of ∼7.5 mol %, which is related to the number of water molecules in the hydration layer around a glycerol molecule. At higher glycerol concentrations, water molecules dispersed in a glycerol network become abundant and eventually dominate, and four distinct relaxation processes emerge in the mixtures.

In a JPCB paper, Nguyen's group has performed terahertz dielectric spectroscopic measurements of aqueous solutions of bovine serum albumin (BSA) and identified important relaxation modes and times of water molecules in such systems, especially water molecules in the hydration shell of the protein. Cheng's group conducted large-scale atomistic molecular dynamics simulations of the same systems and revealed the dynamics of water molecules in the aqueous BSA solutions including those in the protein's hydration shell. The simulation results are in good agreement with the experimental data. The integration of terahertz dielectric spectroscopy and molecular dynamics simulation provides a powerful tool of studying the hydration of macromolecules, molecules, and ions.