Comment on ‘Discussion on novel attractive force between ions in quantum plasmas—failure of simulations based on a density functional approach’

Bönitz, M.; Pehlke, E.; Schoof, Tim

doi:10.1088/0031-8949/88/05/057001

Cited by 37 publications

(18 citation statements)

References 45 publications

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“…The existence of such an attractive potential betweens ions of similar charge has been the subject of intense recent debate. [49][50][51][52][53] However, the long-range structure of the SE electrostatic potential can be oscillatory (Friedel Oscillations). The cohesive properties of ions inside degenerate free electron gas can beautifully describe the metallic binding.…”

Section: Friedel Oscillations and Shukla-eliasson Potentialmentioning

confidence: 99%

Hydrodynamic limit of Wigner-Poisson kinetic theory: Revisited

Akbari-Moghanjoughi

2015

Physics of Plasmas

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In this paper, we revisit the hydrodynamic limit of the Langmuir wave dispersion relation based on the Wigner-Poisson model in connection with that obtained directly from the original Lindhard dielectric function based on the random-phase-approximation. It is observed that the (fourth-order) expansion of the exact Lindhard dielectric constant correctly reduces to the hydrodynamic dispersion relation with an additional term of fourth-order, beside that caused by the quantum diffraction effect. It is also revealed that the generalized Lindhard dielectric theory accounts for the recently discovered Shukla-Eliasson attractive potential (SEAP). However, the expansion of the exact Lindhard static dielectric function leads to a k 4 term of different magnitude than that obtained from the linearized quantum hydrodynamics model. It is shown that a correction factor of 1/9 should be included in the term arising from the quantum Bohm potential of the momentum balance equation in fluid model in order for a correct plasma dielectric response treatment. Finally, it is observed that the long-range oscillatory screening potential (Friedel oscillations) of type cosð2k F rÞ=r 3 , which is a consequence of the divergence of the dielectric function at point k ¼ 2k F in a quantum plasma, arises due to the finiteness of the Fermi-wavenumber and is smeared out in the limit of very high electron number-densities, typical of white dwarfs and neutron stars. In the very low electron number-density regime, typical of semiconductors and metals, where the Friedel oscillation wavelength becomes much larger compared to the interparticle distances, the SEAP appears with a much deeper potential valley. It is remarked that the fourth-order approximate Lindhard dielectric constant approaches that of the linearized quantum hydrodynamic in the limit if very high electron number-density. By evaluation of the imaginary part of the Lindhard dielectric function, it is shown that the Landau-damping region in x-k plane increases dramatically by increase of the electron number-density. V C 2015 AIP Publishing LLC. [http://dx.

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Section: Friedel Oscillations and Shukla-eliasson Potentialmentioning

confidence: 99%

Hydrodynamic limit of Wigner-Poisson kinetic theory: Revisited

Akbari-Moghanjoughi

2015

Physics of Plasmas

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“…Thus our results clearly confirm the recent explanations given in Refs. [30,31] of the invalidity of linearized QHD for the problem of ions in streaming quantum plasmas.…”

Section: Discussionmentioning

confidence: 99%

“…Finally, an even simpler approach that is based on a quantum hydrodynamic model (QHD) has been applied that predicts an attractive interaction between ions even in the absence of streaming, u e = 0 [29]. Comparisons with density functional theory revealed that this is incorrect [30] and points to limitations of QHD models for dense plasmas [31,32]. A recent overview and more references can be found in Ref.…”

Section: Introductionmentioning

confidence: 99%

Ion potential in warm dense matter: Wake effects due to streaming degenerate electrons

et al. 2015

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The effective dynamically screened potential of a classical ion in a stationary flowing quantum plasma at finite temperature is investigated. This is a key quantity for thermodynamics and transport of dense plasmas in the warm dense matter regime. This potential has been studied before within hydrodynamic approaches or based on the zero temperature Lindhard dielectric function. Here we extend the kinetic analysis by including the effects of finite temperature and of collisions based on the Mermin dielectric function. The resulting ion potential exhibits an oscillatory structure with attractive minima (wakes) and, thus, strongly deviates from the static Yukawa potential of equilibrium plasmas. This potential is analyzed in detail for high-density plasmas with values of the Brueckner parameter in the range 0.1 ≤ rs ≤ 1, for a broad range of plasma temperature and electron streaming velocity. It is shown that wake effects become weaker with increasing temperature of the electrons. Finally, we obtain the minimal electron streaming velocity for which attraction between ions occurs. This velocity turns out to be less than the electron Fermi velocity. Our results allow, for the first time, for reliable predictions of the strength of wake effects in nonequilibrium quantum plasmas with fast streaming electrons showing that these effects are crucial for transport under warm dense matter conditions, in particular for laser-matter interaction, electron-ion temperature equilibration and for stopping power.

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“…Note also that the single potential (19) with the given parameters in (6) is valid for both potential forms of monotonic and oscillatory. Because of discrepancy between the above result and the density functional theory (DFT) simulations an intense debate has gone on the validity of the hydrodynamic or DFT theories [57][58][59][60][61][62]. This is because the SE potential gives rise to the Lennard-Jones type attractive potential around the screened ion for a wide range of the electron number density which is well above the metallic density regime.…”

Section: Static Charge Screeningmentioning

confidence: 99%

Ground state energy of hydrogen-like ions in quantum plasmas

2020

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Using the asymptotic iteration method (AIM) we investigate the variation in the 1s energy levels of hydrogen and helium-like static ions in fully degenerate electron gas. The semiclassical Thomas-Fermi (TF), Shukla-Eliasson (SE) and corrected Shukla-Eliasson (cSE) models are compared. It is remarked that these models merge into the vacuum level for hydrogen and helium-like ions in the dilute classical electron gas regime. While in the TF model hydrogen ground state level lifts monotonically towards the continuum limit with increase in the electron concentration, in the SE and cSE models universal bound stabilization valley through the energy minimization occurs at a particular electron concentration range for the hydrogen-like ion which for cSE model closely matches the electron concentrations in typical metals. The later stabilizing mechanism appears to be due to the interaction between plasmon excitations and the Fermi lengthscales in metallic density regime. In the case of helium-like ions, however, no such stability mechanism is found.The application of cSE model with electron exchange and correlation effects reveals that cSE model qualitatively accounts for the number-density and lattice parameters of elemental metals within the framework of free electron assumption. According to the cSE model of static charge screening a simple metal-insulator transition criterion is defined. Current investigation may further elucidate the underlying physical mechanisms in the formation and dielectric properties of metallic compounds.

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Comment on ‘Discussion on novel attractive force between ions in quantum plasmas—failure of simulations based on a density functional approach’

Cited by 37 publications

References 45 publications

Hydrodynamic limit of Wigner-Poisson kinetic theory: Revisited

Hydrodynamic limit of Wigner-Poisson kinetic theory: Revisited

Ion potential in warm dense matter: Wake effects due to streaming degenerate electrons

Ground state energy of hydrogen-like ions in quantum plasmas

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