Exploring water's no-man's land

The investigation of water’s glass transition and a possible liquid-liquid transition within its supercooled state is hampered by its inevitable crystallization in a temperature range, termed “no-man’s land”. Here we report dielectric-spectroscopy and calorimetry measurements of pure water and various aqueous LiCl solutions, part of the latter being quenched to avoid crystallization. By investigating solutions of relatively low salt content and by covering an exceptionally broad frequency range up to THz, we find strong hints at a crossover in water from a strong to a fragile liquid, characterized by different glass-transition temperatures and different non-Arrhenius temperature dependences of the molecular dynamics.