EQUILIBRIUM AND NONEQUILIBRIUM CONTRIBUTIONS TO X-RAY-SCATTERING FROM SUPERCOOLED WATER

Percolation theory for supercooled water predicts an enhanced intensity in the low-q range of the spectrum. In small-angle x-ray measurements on water in the absolute value of q range 0.4-1.8 nm-1 and the temperature range 273-253 K, no enhanced intensity could be measured. The spectra just follow the normal equilibrium thermodynamic behavior. A nonequilibrium enhanced intensity is observed in the spectra of supercooled water in vertically mounted capillaries in the absolute value of q range below 0.3 nm-1. This intensity is due to convection in the capillaries.