Free energy surface of supercooled water
We present a detailed analysis of the free energy surface of a well characterized rigid model for water in supercooled states. We propose a functional form for the liquid free energy, supported by recent theoretical predictions [Y. Rosenfeld and P. Tarazona, Mol. Phys. 95, 141 (1998)], and use it to locate the position of a liquid-liquid critical point at T(C')=130+/-5 K, P(C')=290+/-30 MPa, and rho(C')=1.10+/-0.03 g/cm(3). The observation of the critical point strengthens the possibility that the extended simple point charge model of water may undergo a liquid-liquid phase transition. Finally, we discuss the possibility that the approach to the liquid-liquid critical point could be pre-empted by the glass transition.
Scala
A
Center for Polymer Studies, Center for Computational Science and Department of Physics, Boston University, Boston, Massachusetts 02215 and Dipartmento di Fisica e Istituto Nazionale per la Fisica della Materia, Universita di Roma "La Sapienz.
Starr
FW
La Nave E
Stanley
HE
Sciortino
F