Molecular-dynamics study of a three-dimensional one-component model for distortive phase transitions

Schneider, T.; Stoll, E.

doi:10.1103/physrevb.17.1302

Cited by 1,384 publications

(882 citation statements)

References 21 publications

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“…In this paper, we have avoided these problems by simulating molecules with rigid bonds, and using a Langevin thermostat [32] instead of velocity scaling to set up the thermal gradient. In fact, there is little difference in the critical parameters obtained for the systems with rigid or flexible bonds so long as the vibrational degree of freedom is adequately equilibrated (results not shown).…”

Section: Resultsmentioning

confidence: 99%

“…These regions are thermostatted using a Langevin thermostat [32], while the remainder of the simulation box obeys N V E dynamics. The temperatures are chosen to give the desired magnitude of the thermal gradient ∇T * = (T * hot − T * cold )/(3L * /2), although it must be noted that the local gradient will differ significantly from this simple linear approximation [33].…”

Section: Nemd Simulations In a Temperature Gradientmentioning

confidence: 99%

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Thermo-molecular orientation effects in fluids of dipolar dumbbells

Daub

Åstrand

Bresme

2014

Phys. Chem. Chem. Phys.

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We use molecular dynamics simulations in applied thermal gradients to study thermomolecular orientation (TMO) of size-asymmetric dipolar dumbbells with different molecular dipole moments.We find that the direction of the TMO is the same as in apolar dumbbells of the same size, i.e. the smaller atom in the dumbbell tends to orient towards the colder temperature. The ratio of the electrical polarization to the magnitude of the thermal gradient does not vary much with the magnitude of the molecular dipole moment. We also investigate a novel second order TMO that persists even in size-symmetric dipolar dumbbells where molecules have a slight tendency to orient perpendicular to the gradient except very close to the hot region, where (anti-)parallel orientations are preferred. Finally, we investigate rotational correlation functions and characteristic rotational times in these systems in an attempt to model possible spectroscopic signatures of TMO in experiments. Although we cannot detect any difference in integrated rotational times between equilibrium simulations and simulations in a thermal gradient, more careful modelling of the anisotropic rotational dynamics in the thermal gradient may be more successful.

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Section: Resultsmentioning

confidence: 99%

Section: Nemd Simulations In a Temperature Gradientmentioning

confidence: 99%

Thermo-molecular orientation effects in fluids of dipolar dumbbells

Daub

Åstrand

Bresme

2014

Phys. Chem. Chem. Phys.

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“…The samples were then heated to the desired temperature using a Langevin thermostat [12] with relaxation time parameter of 1 ps and timestep of 1 fs. A Berendsen barostat [13] with relaxation time parameter of 0.01 ps×B, where B is the T=0K bulk modulus, was used to maintain minimal normal This is an author-created, un-copyedited version of an article accepted for publication/published in Modelling and Simulation in Materials Science and Engineering.…”

Section: Lattice Parameter and Thermal Expansionmentioning

confidence: 99%

Thermodynamic properties of average-atom interatomic potentials for alloys

Nöhring

2016

Modelling Simul. Mater. Sci. Eng.

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The atomistic mechanisms of deformation in multicomponent random alloys are challenging to model because of their extensive structural and compositional disorder. For embedded-atom-method interatomic potentials, a formal averaging procedure can generate an average-atom EAM potential and this average-atom potential has recently been shown to accurately predict many zero-temperature properties of the true random alloy. Here, the finite-temperature thermodynamic properties of the average-atom potential are investigated to determine if the average-atom potential can represent the true random alloy Helmholtz Free Energy as well as important finite-temperature properties. Using a thermodynamic integration approach, the average-atom system is found to have an entropy difference of at most 0.05 k B /atom relative to the true random alloy over a wide temperature range, as demonstrated on FeNiCr and Ni 85 Al 15 model alloys. Lattice constants, and thus thermal expansion, and elastic constants are also well-predicted (within a few percent) by the average-atom potential over a wide temperature range. The largest differences between the average atom and true random alloy are found in the zero temperature properties, which reflect the role of local structural disorder in the true random alloy. Thus, the average-atom potential is a valuable strategy for modeling alloys at finite temperatures.

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“…The system is maintained at constant temperature with a Langevin thermostat. 39 Chargecentered WCA ions of diameter (0.001 ≤ σ/L ≤ 0.0122) and characteristic energy ϵ WCA = k B T are confined between two repulsive walls with uniform charge density ±Σ, thickness δ w = L/500, and characteristic energy ϵ w = k B T (eqs 32−37). We evaluate the Coulomb potential with a particle−particle particle−mesh slab Ewald sum 40 with the default accuracy of 10 −4 .…”

Section: Methodsmentioning

confidence: 99%

Electric Double-Layer Structure in Primitive Model Electrolytes: Comparing Molecular Dynamics with Local-Density Approximations

et al. 2015

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ABSTRACT:We evaluate the accuracy of local-density approximations (LDAs) using explicit molecular dynamics simulations of binary electrolytes comprised of equisized ions in an implicit solvent. The Bikerman LDA, which considers ions to occupy a lattice, poorly captures excluded volume interactions between primitive model ions. Instead, LDAs based on the Carnahan− Starling (CS) hard-sphere equation of state capture simulated values of ideal and excess chemical potential profiles extremely well, as well as the relationship between surface charge density and electrostatic potential. Excellent agreement between the EDL capacitances predicted by CS-LDAs and computed in molecular simulations is found even in systems where ion correlations drive strong density and free charge oscillations within the EDL, despite the inability of LDAs to capture the oscillations in the detailed EDL profiles.

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Molecular-dynamics study of a three-dimensional one-component model for distortive phase transitions

Cited by 1,384 publications

References 21 publications

Thermo-molecular orientation effects in fluids of dipolar dumbbells

Thermo-molecular orientation effects in fluids of dipolar dumbbells

Thermodynamic properties of average-atom interatomic potentials for alloys

Electric Double-Layer Structure in Primitive Model Electrolytes: Comparing Molecular Dynamics with Local-Density Approximations

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