Experimental proof of liquid–liquid transition in supercooled water
Diffraction measurements taken whilst laser heating pressurised water from an exotic frozen state
Some theoretical chemists believe many of liquid water’s unusual properties, such as its decrease in density on freezing and its decrease in viscosity on compression, can be explained if, under ambient conditions, it comprises a mixture of two phases that would separate at low temperature and high pressure. Previous experimental attempts to test this, however, have been hamstrung by experimental considerations. Now a new approach, involving laser heating pressurised water from an exotic frozen state, provides more direct verification than ever before.