THEORETICAL DETECTION OF A HDA-LDA LIQUID-LIQUID TRANSITION PHASE FOR WATER USING MOLECULAR SIMULATION

Recent work concerning liquid-phase water simulation and theory suggests that some anomalies observed may be related to a transition between two liquid states, the so called HDA-LDA transition. For example, the density maximum at 4 °C and the minimum in the isothermal compressibility at 46 °C are believed to be due to the existence of this phase transition. In this paper we will present the results of molecular simulations using the TIP4P model for water at very low temperatures and high pressures. In those simulations we were able to obtain a liquid phase transition that can be identified through a change in density. An increase in the coordination number, a discontinuity in water density and a change in the radial distribution function as a function of temperature were observed.