Nonequilibrium processes in repulsive binary mixtures.

We consider rapid cooling processes in classical, three-dimensional, purely repulsive binary mixtures in which an initial infinite-temperature (ideal-gas) configuration is instantly quenched to zero temperature. It is found that such systems display two kinds of ordering processes, the type of which can be controlled by tuning the interactions between unlike particles. While strong inter-species repulsion leads to chemical ordering in terms of an unmixing process, weak repulsion gives rise to spontaneous crystallization, maintaining chemical homogeneity.

Uniaxial-deformation behavior of ice I as described by the TIP4P/Ice and mW water models.

Using molecular dynamics simulations, we assess the uniaxial deformation response of ice I as described by two popular water models, namely, the all-atom TIP4P/Ice potential and the coarse-grained mW model. In particular, we investigate the response to both tensile and compressive uniaxial deformations along the [0001] and crystallographic directions for a series of different temperatures. We classify the respective failure mechanisms and assess their sensitivity to strain rate and cell size.

Uhlenbeck-Ford model: Phase diagram and corresponding-states analysis.

Using molecular dynamics simulations and nonequilibrium thermodynamic-integration techniques we compute the Helmholtz free energies of the body-centered-cubic (bcc), face-centered-cubic (fcc), hexagonal close-packed, and fluid phases of the Uhlenbeck-Ford model (UFM) and use the results to construct its phase diagram. The pair interaction associated with the UFM is characterized by an ultrasoft, purely repulsive pair potential that diverges logarithmically at the origin. We find that the bcc and fcc are the only thermodynamically stable crystalline phases in the phase diagram.