title: Liquid polymorphism, order-disorder transitions and anomalous behavior: A Monte Carlo study of the Bell-Lavis model for water.
abstract: The Bell-Lavis model for liquid water is investigated through numerical simulations. The lattice-gas model on a triangular lattice presents orientational states and is known to present a highly bonded low density phase and a loosely bonded high density phase. We show that the model liquid-liquid transition is continuous, in contradiction with mean-field results on the Husimi cactus and from the cluster variational method. We define an order parameter which allows interpretation of the transition as an order-disorder transition of the bond network. Our results indicate that the order-disorder transition is in the Ising universality class. Previous proposal of an Ehrenfest second order transition is discarded. A detailed investigation of anomalous properties has also been undertaken. The line of density maxima in the HDL phase is stabilized by fluctuations, absent in the mean-field solution.
authors.affiliation: Departamento de Fisica, Universidade Federal do Parana, Caixa Postal 19044, Curitiba 81531, PR, Brazil. fiore@fisica.ufpr.br
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Fiore
authors.forename: Marcia M
authors.initials: MM
authors.lastname: Szortyka
authors.forename: Marcia C
authors.initials: MC
authors.lastname: Barbosa
authors.forename: Vera B
authors.initials: VB
authors.lastname: Henriques
mesh_terms: D008956:Models, Chemical; D009010:Monte Carlo Method; D044367:Phase Transition; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water