Temperature-dependent thermo-elastic properties of s-, p- and d-block liquid metals

Singh, Ranjit; Arafin, Sayyadul; George, A. K.

doi:10.1016/j.physb.2006.04.029

Cited by 29 publications

(27 citation statements)

References 9 publications

(9 reference statements)

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“…Table 3 shows our computed results for βT using equation of state of SW potential. There is a fair agreement between the computed value and the experimental values [20][21][22]. …”

Section: Resultssupporting

confidence: 57%

Transport and Surface Properties of Liquid Metals using their Diffusion Data

Lalneihpuii¹,

Mishra²

2016

stj

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Abstract-The atomic diffusion in liquid Na, K, Cs, Mg, Al, In and Pb have been evaluated from the well-known Einstein'sunder square well (SW) interaction. The friction coefficient, ξ of liquid metals has been computed on the basis of Helfand-Rice-Nachtrieb approach under Helfand's linear trajectory (LT) approximation. Shear viscosity of liquid metals were determined using modified Stokes-Einstein equation for SW potential. Dzugutov's scaling was modified for SW interaction and has been employed to compute excess entropy of the considered liquids. The isothermal compressibility of liquid metals was determined using equation of state of SW potential. Surface entropy of these liquids has been determined through temperature derivative of surface tension. Dzugutov's scaling law has also been tested in these liquid metals. It is found that the various transport and surface properties of these liquid metals extracted from the diffusion coefficients are in a good agreement with the experimental data.

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“…Table 3 shows our computed results for βT using equation of state of SW potential. There is a fair agreement between the computed value and the experimental values [20][21][22]. …”

Section: Resultssupporting

confidence: 57%

Transport and Surface Properties of Liquid Metals using their Diffusion Data

Lalneihpuii¹,

Mishra²

2016

stj

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“…In Fig. 3(b) we reanalyze experimental data for 20 metallic liquids [44], including metals where ab initio density functional theory calculations show hidden-scale invariance [45]. For the mono atomic metallic liquids, the scaling exponent of excess entropy is estimated using…”

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confidence: 99%

Experimental Evidence for a State-Point-Dependent Density-Scaling Exponent of Liquid Dynamics

et al. 2019

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A large class of liquids have hidden scale invariance characterized by a scaling exponent. In this letter we present experimental evidence that the scaling exponent of liquid dynamics is statepoint dependent for the glass-forming silicone oil tetramethyl-tetraphenyl-trisiloxane (DC704) and 5-polyphenyl ether (5PPE). From dynamic and thermodynamic properties at equilibrium, we use a method to estimate the value of γ at any state point of the pressure-temperature plane, both in the supercooled and normal liquid regimes. We find agreement between the average exponents and the value obtained by superposition of relaxation times over a large range of state-points. We confirm the state-point dependence of γ by reanalyzing data of 20 metallic liquids and two model liquids.Decreasing the temperature (T ) or increasing the density (ρ) by applying pressure of liquids lead to slowing down of the molecular dynamics and eventually a glass transition if crystallization is avoided [1,2]. It has been demonstrated that for numerous low molecular weight liquids and polymers, the relaxation time or other dynamic quantities can be superimposed onto a master curve within the experimental uncertainty when plotted as a function of ρ γ /T . The scaling exponent γ is thus sometimes referred to as a material constant [3][4][5]. In this letter, we show that γ is in fact state-point dependent and can be measured at a single state point. In the following we will use subscripts to distinguish definitions of γ's.Let τ be the structural relaxation time measured from the loss-peak frequency of the electric permittivity. We will express τ in reduced units of m/k B T ρ 2/3 where m is a atomic/molecular/polymer-segment mass and define the scaling exponent of τ as [6]In this general definition the exponent depends on the state point and the fixed quantity (τ in the above case). A physical interpretation of γ τ is that it quantifies the relative contribution of volume and thermal energy to the temperature evolution of the molecular mobility [7]. Similar to the structural relaxation time, configurational adiabats can also be associated with a scaling exponent:In general, two scaling exponents of different observables (structural, dynamical or thermodynamic) will have different values. However, if the system has so-called "hidden scale-invariance" [6, 8] then all scaling exponents of different properties will have the same value. In Ref.[9] * asanz@ruc.dk † urp@ruc.dk it was experimentally shown that γ τ = γ Sex at one state point of the silicone oil DC704. This result is spectacular since hidden scale-invariance can only be present in a class of systems [10,11]. This class is believed to include systems where van der Waals (vdW) interactions dominate, but exclude systems where hydrogen-bondes (HB) dominates the Hamiltonian [12]. The isomorph theory [6,8,10,12] is a framework for describing systems where the potential energy function U (R) possesses hidden scale invariance (here, R is the collective coordinate of the system). Formally hidden scale inva...

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“…The IPL model exhibit a polymorphic cp-bcc transition when γ < 2.5 also seen for many metals [40,78,79]. Thus, at the triple point elements with γ < 2.5 are expected [34] to form bcc crystals while elements with γ > 2.5 are ex- [71] of cv, αp and KT (using Eq. (7)), and σ = 1.094 was chosen to match that of the solid-liquid coexistence shown in Fig.…”

Section: E Revisiting the Inverse Power-law Modelmentioning

confidence: 90%

“…See legend andTable Ifor more details. Density scaling exponents from experimental thermodynamic data collected in Ref [71]. compared to ab initio DFT computations for liquids.…”

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confidence: 99%

Hidden scale invariance of metals

et al. 2015

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Density functional theory (DFT) calculations of 58 liquid elements at their triple point show that most metals exhibit near proportionality between thermal fluctuations between virial and potential-energy in the isochoric ensemble. This demonstrates a general "hidden" scale invariance of metals making the dense part of the thermodynamic phase diagram effectively one dimensional with respect to structure and dynamics. DFT computed density scaling exponents, related to the Gr{\"u}neisen parameter, are in good agreement with experimental values for 16 elements where reliable data were available. Hidden scale invariance is demonstrated in detail for magnesium by showing invariance of structure and dynamics. Computed melting curves of period three metals follow curves with invariance (isomorphs). The experimental structure factor of magnesium is predicted by assuming scale invariant inverse power-law (IPL) pair interactions. However, crystal packings of several transition metals (V, Cr, Mn, Fe, Nb, Mo, Ta, W and Hg), most post-transition metals (Ga, In, Sn, and Tl) and the metalloids Si and Ge cannot be explained by the IPL assumption. Thus, hidden scale invariance can be present even when the IPL-approximation is inadequate. The virial-energy correlation coefficient of iron and phosphorous is shown to increase at elevated pressures. Finally, we discuss how scale invariance explains the Gr{\"u}neisen equation of state and a number of well-known empirical melting and freezing rules.Comment: 12 pages, 11 figure

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Temperature-dependent thermo-elastic properties of s-, p- and d-block liquid metals

Cited by 29 publications

References 9 publications

Transport and Surface Properties of Liquid Metals using their Diffusion Data

Transport and Surface Properties of Liquid Metals using their Diffusion Data

Experimental Evidence for a State-Point-Dependent Density-Scaling Exponent of Liquid Dynamics

Hidden scale invariance of metals

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