Quantitative investigation of the two-state picture for water in the normal liquid and the supercooled regime

S.R. ACCORDINO; J.A. RODRIGUEZ FRIS; F. SCIORTINO; G.A. APPIGNANESI

Eur. Phys. J. E

Springer-Verlag

Año: 2011 vol. 34 p. 1 - 7

1292-8941

Several evidences have helped to establish the two-state nature of liquid water. Thus, within thenormal liquid and supercooled regimes water has been shown to consist of a mixture of well-structured,low-density molecules and unstructured, high-density ones. However, quantitative analyses have faced theburden of unambiguously determining both the presence and the fraction of each kind of water ?species?.A recent approach by combining a local structure index with potential-energy minimisations allows us toovercome this difficulty. Thus, in this work we extend such study and employ it to quantitatively determinethe fraction of structured molecules as a function of temperature for different densities. This enables us tovalidate predictions of two-state models.