We present an analysis of ice nucleation kinetics from near-ambient pressure water as temperature decreases below the homogeneous limit TH by cooling micrometer-sized droplets (microdroplets) evaporatively at 103-104 K/s and probing the structure ultrafast using femtosecond pulses from the Linac Coherent Light Source (LCLS) free-electron X-ray laser. Below 232 K, we observed a slower nucleation rate increase with decreasing temperature than anticipated from previous measurements, which we suggest is due to the rapid decrease in water's diffusivity. This is consistent with earlier findings that microdroplets do not crystallize at <227 K, but vitrify at cooling rates of 106-107 K/s. We also hypothesize that the slower increase in the nucleation rate is connected with the proposed "fragile-to-strong" transition anomaly in water.
- X-ray free-electron laser
- fragile to strong liquid transition
- homogeneous ice nucleation
- supercooled water
ASJC Scopus subject areas
- General Materials Science
- Physical and Theoretical Chemistry