The Water Polymorphism and the Liquid–Liquid Transition from Transport Data

NMR Spectroscopic literature data are used, in a wide temperature-pressure range 1 (180-350K and 0.1-400 MPa) to study the water polymorphism and the validity of the liquid-liquid 2 transition (LLT) hypothesis. We have considered self-diffusion coefficient DS and the reorientational 3 correlation time tq (obtained from spin-lattice T1 relaxation times), measured respectively in bulk 4 and emulsioned liquid water from the stable to well inside the metastable supercooled region. As an 5 effect of the hydrogen bond (HB) networking the isobars of both these transport functions evolve 6 with T by changing of several order of magnitude, whereas their pressure dependence become 7 more and more pronounced going towards lower temperatures.Both these transport functions were 8 then studied according to the Adam-Gibbs model, typical of glass forming liquids, obtaining the 9 waterconfigurational entropy and the corresponding specific heat contribution.The comparison 10 of the evaluated CP,con f isobars with the experimentallymeasured water specific heat reveals the 11 fully consistence of this analysis.In particular, the observed CP,con f maxima and his diverging 12 behaviorsclearly reveals the presence of the LLT and with a reasonable approximation the liquid 13 liquid critical point (LLCP) locus in the phase diagram.