High-pressure equation of state for solid krypton from interatomic potentials

Barker, John A.

doi:10.1007/bf01011653

Cited by 21 publications

(2 citation statements)

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“…7,8, and 41. Loubeyre [7] using the self-consistent phonon approximation and Barker [41] using Monte Carlo method on the base of the same pair plus three-body intermolecular potential obtained that the pressure is somewhat underestimated compared to experiment. On this ground Barker concluded that the three-body exchange term is too high and that the best agreement with experiment can be obtained using the Axilrod-Teller interaction as the only many-body interaction.…”

Section: Solid Ar Kr and Xementioning

confidence: 99%

Many-body interactions and high-pressure equations of state in rare-gas solids

Freǐman

Tretyak

2007

Low Temperature Physics

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The T = 0 K equations of state (EOS) of rare-gas solids (RGS) (He, Ne, Ar, Kr, and Xe) are calculated in the experimentally studied ranges of pressures accounting for two-and three-body interatomic forces. Solid-state corrections to the pure two-body Aziz et al. potentials included the long-range Axilrod-Teller three-body interaction and short-range three-body exchange interaction. The energy-scale and length-scale parameters of the latter were taken as adjustable parameters of theory. The calculated T = 0 K EOS for all RGS are in excellent agreement with experiment in the whole range of pressures. The calculated EOS for Ar, Kr, and Xe exhibit inflection points where the isothermal bulk moduli have non-physical maxima indicating that account of only three-body forces becomes insufficient. These points lie at pressures 250, 200, and 175 GPa (volume compressions of approximately 4.8, 4.1, and 3.6) for Ar, Kr, and Xe, respectively. No such points were found in the calculated EOS of He and Ne. The relative magnitude of the three-body contribution to the ground-state energy with respect to the two-body one as a function of the volume compression was found to be non-monotonic in the sequence NeAr -Kr-Xe. In a large range of compressions, Kr has the highest value of this ratio. This anomally high three-body exchange forces contributes to the EOS so large negative pressure that the EOS for Kr and Ar as a function of compression nearly coincide. At compressions higher approximately 3.5, the curves intersect and further on the EOS of Kr lies lower than that of Ar. PACS: 64.60.Cn Order-disorder transformations; statistical mechanics of model systems; 67.80.-s Solid helium and related quantum crystals; 67.90.+z Other topics in quantum fluids and solids; liquid and solid helium.

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Section: Solid Ar Kr and Xementioning

confidence: 99%

Many-body interactions and high-pressure equations of state in rare-gas solids

Freǐman

Tretyak

2007

Low Temperature Physics

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“…35 Barker and coworkers had shown that representing the total potential energy of a many-body system as a pairwise additive sum of the best available two-body potentials plus the ATM terms yielded predictions for the properties of bulk solid, liquid, and gaseous rare gas systems in very good agreement with experiment over a wide range of conditions. [46][47][48][49][50][51] This indicates that the triple-dipole dispersion energies provide a good effective representation of the overall nonadditive energy for such nonpolar species, albeit at least partly because of mutual cancellations of other types of nonadditive energies. 49,[52][53][54][55] For heterogeneous SF 6 -͑Ar͒ n and SF 6 -͑Kr͒ n cluster systems, including such terms significantly affects the melting temperatures determined from classical Monte Carlo and molecular dynamics simulations.…”

Section: Introductionmentioning

confidence: 99%

How do quantum effects change conclusions about heterogeneous cluster behavior based on classical mechanics simulations?

Chartrand

Roy

1998

The Journal of Chemical Physics

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Comparisons of classical and quantum Monte Carlo simulation of SF 6-͑Ar͒ n and SF 6-͑Ne͒ n clusters are used to examine whether certain novel types of behavior seen in classical simulations of SF 6-͑Ar͒ n and SF 6-͑Kr͒ n persist when quantum effects are taken into account. For mixed clusters formed from Ar ͑and presumably other heavy partners͒ quantum effects have little effect on calculated properties, even at very low temperatures, so the cluster-size-dependent preference for solvation vs phase separation and ''reverse melting'' behavior found in the classical simulations may be expected to occur in many heterogeneous systems. On the other hand, quantum effects substantially lower the melting temperatures of clusters formed with Ne, and ͑except for a couple of unusually stable stacked isomers͒ effectively remove the barriers separating the maximally-solvated and phase-separated forms, implying that the latter will normally not exist. Moreover, for ͑at least͒ the SF 6-͑Ne͒ 11 species, when quantum effects are taken into account there is little evidence of solidlike behavior down to the lowest temperatures accessible to our simulation ͑0.4 K͒, although classical simulations show a sharp freezing transition at 1.5(Ϯ0.1) K. Inclusion of three-body triple-dipole Axilrod-Teller-Muto interactions in the overall potential energy has little effect on either quantum or classical Ne cluster simulations.

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