arXiv subjects

Nicholas Bailey

Publications and source records attributed to Nicholas Bailey.

3 recordsLinked to original sources

arXiv2008

Density scaling as a property of strongly correlating viscous liquids

We address a recent conjecture according to which the relaxation time $τ$ of a viscous liquid obeys density scaling ($τ=F(ρ^γ/T)$ where $ρ$ is density) if the liquid is ``strongly correlating,'' i.e., has almost 100% correlation between equilibrium virial and potential-energy fluctuations [Pedersen {\it et al.}, PRL {\bf 100}, 011201 (2008)]. Computer simulations of two model liquids - an asymmetric dumbbell model and the Lewis-Wahnström OTP model - confirm the conjecture and demonstrate that the scaling exponent $γ$ can be accurately predicted from equilibrium fluctuations.

cond-mat.soft↗

arXiv2007

Strong pressure-energy correlations in van der Waals liquids

Strong correlations between equilibrium fluctuations of the configurational parts of pressure and energy are found in the Lennard-Jones liquid and other simple liquids, but not in hydrogen-bonding liquids like methanol and water. The correlations, that are present also in the crystal and glass phases, reflect an effective inverse power-law repulsive potential dominating fluctuations, even at zero and slightly negative pressure. In experimental data for supercritical Argon, the correlations are found to be approximately 96%. Consequences for viscous liquid dynamics are discussed.

cond-mat.stat-mech↗

arXiv2006

Digital Material: a flexible atomistic simulation code

The complexities of today's materials simulations demand computer codes which are both powerful and highly flexible. A researcher should be able to readily choose different geometries, different materials and different algorithms without having to write low-level code and recompile each time. We describe a molecular dynamics (MD) code, called Digital Material, in which we have sought to maximize flexibility without sacrificing efficiency. Our approach starts from the software engineering concept of Design Patterns and involves dividing the work of an MD simulation into well-defined components. The bulk of this paper is taken up with a detailed description of the different components, their interfaces and implementations and the reasoning behind these. The level of detail is not at the line-by-line level, but at such a level that a reader could implement a similar code sharing the same design principles.

cond-mat.other↗