Simulações entrópicas do modelo de Bell-Lavis para a água

• Autor(a) principal: Ferreira, Lucas de Souza
• Data de Publicação: 2020
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/10770
• topic: Modelo de Bell-Lavis; Simulações entrópicas; Modelo de Ising; Transições de fase; Phase transition; Bell-Lavis model; Entropic simulation; Ising model; CIENCIAS EXATAS E DA TERRA::FISICA

In this work we used the entropic sample simulation to study the Bell-Lavis model for the liquid water. We estimed the joint density of states with which we obtain the average of the termodynamic properties of the energy, specific heat, density of particles, hydrogen bond energies, and the susceptibility of the density of particles to many values of the constants H and μ. Through of the analyze of this quantities we determined the possible ground states and the values for H and μ for which happen the transition between the ground states. We observe that for H = 1, 0 and 0, 0 < μ < 0, 5 the density of particles shows a maximum associated to transition from a configuration of low density to a configuration of high density. In this range the specific heat show two maxima, the first associated to maximum in the density, and do not shows finite size effects , and the second a transition order disorder. For 0.5 < μ < 1.5 we have only one maximum for the specific heat which is the fusion of the two before. We performed a finite size scaling study for μ = 1, 0 observing the thermodynamic quantities that characterize a second order fase transition and we found a critical temperature Tc = 0, 510718(49), while when observing the thermodynamic quantities that characterize a first order fase transition we obtain Tc = 0, 564520(37). Such results indicate the presence of two orders of phase transitions at very close temperatures. For understand the behavior we analise the order parameter to the one dimensional Ising model and conclude that the right choice of the order parameter for the model is decisive to visualize the phase transition. For the Bell-Lavis model the choice of this parameter is yet a challenge to be overcome.