Activity-induced liquid–liquid phase transition in supercooled water

Using an activation model that reproduces facilitation mechanisms, we recently found a fluidization transition in supercooled water triggered by the motion of a few active molecules. The fluidization transition was also found in a supercooled model liquid, suggesting its universality. We show here that this transition triggers a structural change in water, in favor of the high-density liquid water (HDL) structure that is less organized, resulting in an activation-induced liquid–liquid structural phase transition between low-density liquid water and high-density liquid water (HDL).