This paper is the fourth in a series devoted to identifying and explaining properties of strongly correlating liquids, i.e., liquids where virial potential energy correlate better than 90% their thermal equilibrium fluctuations NVT ensemble. For such we here introduce concept "isomorphic" curves phase diagram. A number thermodynamic, static, dynamic isomorph invariants are identified. These include excess entropy, isochoric specific heat, reduced-unit static correlation functions, as well...

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

We show that a number of model liquids at fixed volume exhibit strong correlations between equilibrium fluctuations the configurational parts (instantaneous) pressure and energy. present detailed results for 13 systems, showing in which systems these are significant. These include Lennard-Jones (both single- two-component) several other simple liquids, neither hydrogen-bonding such as methanol water, nor Dzugutov liquid, has significant contributions to second nearest neighbor distance. The...

We present a detailed analysis and discuss consequences of the strong correlations configurational parts pressure energy in their equilibrium fluctuations at fixed volume reported for simulations several liquids previous paper [N. P. Bailey et al., J. Chem. Phys. 129, 184507 (2008)]. The concentrates specifically on single-component Lennard-Jones system. demonstrate that potential may be replaced, volume, by an effective power law but not simply because only short-distance encounters...

Although the freezing of liquids and melting crystals are fundamental for many areas sciences, even simple properties like temperature-pressure relation along line cannot be predicted today. Here we present a theory in which coexisting crystal liquid phases at single thermodynamic state point provide basis calculating pressure, density entropy fusion as functions temperature line, well variation this reduced crystalline vibrational mean-square displacement (the Lindemann ratio), liquid's...

RUMD is a general purpose, high-performance molecular dynamics (MD) simulation package running on graphical processing units (GPU’s). addresses the challenge of utilizing many-core nature modern GPU hardware when simulating small to medium system sizes (roughly from few thousand up hundred particles). It has performance that comparable other GPU-MD codes at large and substantially better smaller sizes. open-source consists library written in C++ CUDA extension C, an easy-to-use Python...

The liquid structure of a glass-forming binary alloy is studied using molecular dynamics simulations. analysis employs the geometrical approach Frank and Kasper to establish that supercooled contains extended clusters characterized by same short range order as crystal. steep increase in heat capacity on cooling directly coupled growing fluctuations Frank-Kasper clusters. relaxation particles dominates slow tail self-intermediate scattering function.

A well-known result of liquid state theory is that the structure dense fluids mainly determined by their repulsive forces. The Weeks-Chandler-Andersen potential, which cuts intermolecular potentials at minima, therefore often used as a reference. However, this cannot reproduce viscous dynamics Kob-Andersen binary Lennard-Jones [Berthier and Tarjus, Phys. Rev. Lett. 103, 170601 (2009)]. This paper shows inverse-power-law provide reference for reproduces its structure, dynamics, isochoric heat...

Results from molecular dynamics simulations of two viscous model liquids -- the Lewis-Wahnstrom ortho-terphenyl and an asymmetric dumbbell are reported. We demonstrate that have a ``hidden'' approximate scale invariance: Equilibrium potential energy fluctuations accurately described by inverse power law (IPL) potentials, radial distribution functions reproduced IPL's, obey IPL predicted scaling properties to good approximation. also applies with exponent equilibrium fluctuations. In...

This series of papers is devoted to identifying and explaining the properties strongly correlating liquids, i.e., liquids with more than 90% correlation between their virial W potential energy U fluctuations in NVT ensemble. Paper IV [N. Gnan et al., J. Chem. Phys. 131, 234504 (2009)] showed that have "isomorphs," which are curves phase diagram along structure, dynamics, some thermodynamic invariant reduced units. In present paper, using fact reduced-unit radial distribution functions...

We propose an approach for computing the Gibbs free energy difference between phases of a material. The method is based on determination average force acting interfaces that separate two interest. This force, which depends phases, computed by applying external harmonic field couples to parameter specifies phases. Validated first Lennard-Jones model, we demonstrate flexibility, efficiency, and practical applicability this melting temperatures sodium, magnesium, aluminum, silicon at ambient...

Computing phase diagrams of model systems is an essential part computational condensed matter physics. In this paper, we discuss in detail the interface pinning (IP) method for calculation Gibbs free energy difference between a solid and liquid. This done single equilibrium simulation by applying harmonic field that biases system towards two-phase configurations. The phases determined from average force applied exerts on system. As test system, study Lennard-Jones model. It shown coexistence...

The binary Kob-Andersen (KA) Lennard-Jones mixture is the standard model for computational studies of viscous liquids and glass transition. For very long simulations, KA system crystallizes, however, by phase separating into a pure $A$ particle forming fcc crystal. We present thermodynamic diagram KA-type mixtures consisting up to 50% small ($B$) particles showing, in particular, that melting temperature at liquid density 1.2 1.028(3) units. At large $B$ concentrations, crystallizes CsCl...

At density 1.2 the Kob-Andersen binary Lennard-Jones liquid partly crystallizes in temperature interval [0.39, 0.44] after typically 10-100 microseconds (Argon units). The crystallization is initiated by a phase separation where large (A) particles cluster volume void of B particles. We investigate modification system attraction between same type removed, thus disfavoring separation. have not been able to crystallize this new system.

Density functional theory (DFT) calculations of 58 liquid elements at their triple point show that most metals exhibit near proportionality between the thermal fluctuations virial and potential energy in isochoric ensemble. This demonstrates a general ``hidden'' scale invariance making condensed part thermodynamic phase diagram effectively one dimensional with respect to structure dynamics. DFT computed density scaling exponents, related Gr\"uneisen parameter, are good agreement experimental...

The noble elements constitute the simplest group of atoms. At low temperatures or high pressures, they freeze into face-centered cubic (fcc) crystal structure (except helium). This paper investigates neon, argon, krypton, and xenon by molecular dynamics using simplified atomic potentials recently proposed Deiters Sadus [J. Chem. Phys. 150, 134504 (2019)], which are parameterized data from accurate ab initio quantum-mechanical calculations coupled-cluster approach at single-double-triple...

In this third paper of the series, which started with [N. P. Bailey et al., J. Chem. Phys. 129, 184507 and 184508 (2008)], we continue development theoretical understanding strongly correlating liquids - those whose instantaneous potential energy virial are correlated in their thermal equilibrium fluctuations at constant volume. The existence such was detailed previous work identified them, based on computer simulations, as a large class liquids, including van der Waals but not, e.g.,...

This paper shows by computer simulations that some crystalline systems have curves in their thermodynamic phase diagrams, so-called isomorphs, along which structure and dynamics reduced units are invariant to a good approximation. The crystals studied classical-mechanical framework, is generally description except significantly below melting. existence of isomorphs for validated particles interacting via the Lennard-Jones pair potential arranged into face-centered cubic (FCC) structure; slow...

A large class of liquids obey density scaling characterized by an exponent, which quantifies the relative roles temperature and for dynamics. We present experimental evidence that density-scaling exponent γ is state-point dependent glass formers tetramethyl-tetraphenyl-trisiloxane (DC704) 5-polyphenyl ether (5PPE). method proposed from dynamic thermodynamic properties at equilibrium estimates value γ. The applies any state point pressure-temperature plane, both in supercooled normal liquid...

Molecular dynamics results for the dynamic Prigogine-Defay ratio are presented two glass-forming liquids, thus evaluating experimentally relevant quantity testing whether metastable-equilibrium liquid is described by a single parameter to good approximation. For Kob-Andersen binary Lennard-Jones mixture as well an asymmetric dumbbell model liquid, single-parameter description works quite well. This confirmed time-domain where it found that energy and pressure fluctuations strongly correlated...

This paper argues that the viscosity of simple fluids at densities above triple point is a specific function temperature relative to freezing density in question. The proposed expression, which arrived part by reference isomorph theory systems with hidden scale invariance, describes computer simulations Lennard-Jones system as well argon and methane experimental data simulation results for an effective-pair-potential model liquid sodium.