STRUCTURAL CHARACTERIZATION OF AN ELECTROLYTIC AQUEOUS-SOLUTION, LICL-CENTER-DOT-6H(2)O, IN THE GLASS, SUPERCOOLED LIQUID, AND LIQUID STATES

Using the technique of hydrogen and deuterium substitution, the struct ure of water in concentrated lithium chloride aqueous solutions (LiCl . 6H(2)O) is explored for the liquid, supercooled liquid, and glass st ates. It is found that changes in structure between the glass and supe rcooled states are minor, but that a major change in water structure o ccurs as the supercooled liquid is heated above the temperature of per itexy of the penta-hydrate (T-p = 207 K). In particular the 4.4 Angstr om peak in the OO pair correlation function of pure water, which is no rmally viewed as indicating tetrahedral short range coordination in wa ter, is absent in the LiCl solution at the same temperature, but reapp ears strongly in the glass and supercooled states. Corresponding chang es occur in the HH and OH correlation functions. In addition, correlat ions appear to extend nearly twice as far in the glass and supercooled liquid, compared to the room temperature liquid. (C) 1995 American In stitute of Physics.