Oliveira, Alan Barros deBarbosa, Márcia Cristina Bernardes2012-10-012012-10-012005OLIVEIRA, A. B. de; BARBOSA, M. C. B. Density anomaly in a competing interactions lattice gas model. Journal of Physics. Condensed Matter, v. 17, n. 3, p. 399-411, 2005. Disponível em: <https://iopscience.iop.org/article/10.1088/0953-8984/17/3/001>. Acesso em: 01 out. 2012.1361648Xhttp://www.repositorio.ufop.br/handle/123456789/1489Water and other tetrahedral liquids are characterized by a density anomaly whose origin is not well understood. A very simple model of a short-range attraction followed by an outer shell repulsion is proposed as a test potential for the density anomaly. We show that these competing interactions when applied to a two-dimensional lattice gas leads to the formation of two liquid phases and to the appearance of a density anomaly. The coexistence line between the two liquid phases meets a critical line between the fluid and the low-density liquid phase at a tricritical point. The line ofmaximum density emerges in the vicinity of the tricritical point, close to the demixing transition.en-USArtigo publicado em periodicohttps://iopscience.iop.org/article/10.1088/0953-8984/17/3/001