Temperature, pressure and volume dependence of the Grüneisen parameter of dense gaseous and liquid argon

Amorós, J.; Solana, J. R.; Villar, Eugenio

doi:10.1016/0254-0584(88)90065-x

Cited by 8 publications

(9 citation statements)

References 6 publications

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“…The GP was also calculated in liquid Ar in a small range of pressure and temperature and was found to decrease on isobaric heating [14]. In a wider temperature and pressure range, γ in Ar in the dense gas and liquid state increases on isothermal compression and is nearly constant on isochoric heating [15]. γ was also calculated from ensemble averages of fluctuations [16].…”

Section: Introductionmentioning

confidence: 99%

Supercritical Grüneisen parameter and its universality at the Frenkel line

et al. 2017

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We study the thermomechanical properties of matter under extreme conditions deep in the supercritical state, at temperatures exceeding the critical one by up to four orders of magnitude. We calculate the Grüneisen parameter γ and find that on isochores it decreases with temperature from 3 to 1, depending on the density. Our results indicate that from the perspective of thermomechanical properties, the supercritical state is characterized by a wide range of γ's which includes solidlike values-an interesting finding in view of the common perception of the supercritical state as being an intermediate state between gases and liquids. We rationalize this result by considering the relative weights of oscillatory and diffusive components of the supercritical system below the Frenkel line. We also find that γ is nearly constant at the Frenkel line above the critical point and explain this universality in terms of the pressure and temperature scaling of system properties along the lines where particle dynamics changes qualitatively.

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Section: Introductionmentioning

confidence: 99%

Supercritical Grüneisen parameter and its universality at the Frenkel line

et al. 2017

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“…They also found a strong positive correlation with temperature, much like our findings for MgO, in contrast to the near temperature-independent behavior of solids. Since then, similar behavior has been seen for a wide array of liquids, including: cryogenic Ar; organic solvents like pentane, ethanol and methanol; metallic liquids like mercury; and a variety of silicates in the CMASF compositional system (Boehler and Ramakrishnan, 1980;Brown et al, 1987;Amoros et al, 1988;Asimow, 2012).…”

Section: Understanding the Grü Neisen Parameter Evolution Of Liquidsmentioning

confidence: 68%

Coordinated Hard Sphere Mixture (CHaSM): A simplified model for oxide and silicate melts at mantle pressures and temperatures

Wolf

Asimow

Stevenson

2015

Geochimica et Cosmochimica Acta

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We develop a new model to understand and predict the behavior of oxide and silicate melts at extreme temperatures and pressures, including deep mantle conditions like those in the early Earth magma ocean. The Coordinated Hard Sphere Mixture (CHaSM) is based on an extension of the hard sphere mixture model, accounting for the range of coordination states available to each cation in the liquid. By utilizing approximate analytic expressions for the hard sphere model, this method is capable of predicting complex liquid structure and thermodynamics while remaining computationally efficient, requiring only minutes of calculation time on standard desktop computers. This modeling framework is applied to the MgO system, where model parameters are trained on a collection of crystal polymorphs, producing realistic predictions of coordination evolution and the equation of state of MgO melt over a wide range of pressures and temperatures. We find that the typical coordination number of the Mg cation evolves continuously upward from 5.25 at 0 GPa to 8.5 at 250 GPa. The results produced by CHaSM are evaluated by comparison with predictions from published first-principles molecular dynamics calculations, indicating that CHaSM is accurately capturing the dominant physics controlling the behavior of oxide melts at high pressure. Finally, we present a simple quantitative model to explain the universality of the increasing Grü neisen parameter trend for liquids, which directly reflects their progressive evolution toward more compact solid-like structures upon compression. This general behavior is opposite that of solid materials, and produces steep adiabatic thermal profiles for silicate melts, thus playing a crucial role in magma ocean evolution.

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“…Amoros et. al [46] notice that γ G is only a function of density to a good approximation. This is explained by the fact that Λ in Eq.…”

Section: Hidden Scale Invariancementioning

confidence: 97%

“…Within the accuracy of the Dulong-Petit approximation, c V ≃ 3k B , then γ ≃ 2γ G −2/3. The value of the Grüneisen parameter is γ G = 2.9 [25,46] near the gas-liquid-solid triple point of Ar. This corresponds to γ = 5.1, and is in good agreement with the value obtained by the SAAP potential (Fig.…”

Section: Hidden Scale Invariancementioning

confidence: 99%

Solid-liquid coexistence of the noble elements. I. Theory illustrated by the case of argon

Singh,

Dyre,

Pedersen

2020

Preprint

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The noble elements constitute the simplest group of atoms. At low temperatures or high pressures they freeze into the face-centered cubic (fcc) crystal structure (except helium). We perform molecular dynamics using the recently proposed simplified ab initio atomic (SAAP) potential [Deiters and Sadus, J. Chem. Phys. 150, 134504 (2019)] . This potential is parameterized using data from accurate ab initio quantum mechanical calculations by the coupled-cluster approach on the CCSD(T) level. We compute the fcc freezing lines for Argon and find a great agreement with the experimental values. At low pressures, this agreement is further enhanced by using many-body corrections.Hidden scale invariance of the potential energy function is validated by computing lines of constant excess entropy (configurational adiabats) and shows that mean square displacement and the static structure factor are invariant. These lines (isomorphs) can be generated from simulations at a single state-point by having knowledge of the pair potential. The isomorph theory for the solid-liquid transition is used to accurately predict the shape of the freezing line in the pressure-temperature plane, the shape in the density-temperature plane, the entropy of melting and the Lindemann parameters along the melting line. We finally predict that the body-centered cubic (bcc) crystal is stable at high pressures.

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Temperature, pressure and volume dependence of the Grüneisen parameter of dense gaseous and liquid argon

Cited by 8 publications

References 6 publications

Supercritical Grüneisen parameter and its universality at the Frenkel line

Supercritical Grüneisen parameter and its universality at the Frenkel line

Coordinated Hard Sphere Mixture (CHaSM): A simplified model for oxide and silicate melts at mantle pressures and temperatures

Solid-liquid coexistence of the noble elements. I. Theory illustrated by the case of argon

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