Structural crossover in supercritical water

We have recently shown that supercritical fluids exist in two qualitatively distinct states separated by the "Frenkel line". This theoretical prediction has been confirmed by experimental X-ray studies on Ne and CH4 samples. However, it has never been experimentally observed in water. We have performed computational simulations of the behaviour of water above and below the Frenkel line, and here seek to test these for the first time by neutron scattering on SANDALS. Using samples of different deuteration levels, we will isolate the partial pair distribution functions as a function of pressure. Supercritical water is of exceptional industrial importance for environmentally friendly cleaning and destruction of hazardous waste; thus as well as being of value from a fundamental scientific perspective, our results will point the way towards commercial exploitation of this novel behaviour.