Structure of expanded fluid Rb and Cs: a quantum molecular dynamics study

Kietzmann, André; Redmer, R.; Hensel, F.; Desjarlais, M. P.; Mattsson, Thomas R.

doi:10.1088/0953-8984/18/24/002

Cited by 15 publications

(14 citation statements)

References 35 publications

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“…[27] . Such a feature has been predicted within chemical models earlier [28] and demonstrated recently for Rb [29,30] by QMD simulations in this region.…”

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confidence: 71%

Complex Behavior of Fluid Lithium under Extreme Conditions

et al. 2008

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Lithium is a prototypical simple metal at standard conditions which is well described within the nearly free electron model. However, by changing the density towards expanded or compressed states, the electrical conductivity shows strong and partly unexpected variations. We have performed quantum molecular dynamics simulations for fluid lithium for a wide range of densities and temperatures in order to derive the equation of state, the electrical conductivity, and information about structural and electronic changes along the expansion or compression. Based on these results, we can give a consistent description of the electrical conductivity from the nonmetallic expanded fluid up to the degenerate electron liquid at high densities.

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“…[27] . Such a feature has been predicted within chemical models earlier [28] and demonstrated recently for Rb [29,30] by QMD simulations in this region.…”

supporting

confidence: 71%

Complex Behavior of Fluid Lithium under Extreme Conditions

et al. 2008

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“…The availability of a reliable pseudopotential, which described structure and then dynamics quite well, prompted many classical MD simulation studies; see for example [42][43][44][45][46][47]. Later on first-principles methods have also been applied to simulate liquid rubidium [48][49][50].…”

Section: Introductionmentioning

confidence: 99%

Stokes-Einstein relation of the liquid metal rubidium and its relationship to changes in the microscopic dynamics with increasing temperature

Demmel

Tani

2018

Phys. Rev. E

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For liquid rubidium the Stokes-Einstein (SE) relation is well fulfilled near the melting point with an effective hydrodynamic diameter, which agrees well with a value from structural investigations. A wealth of thermodynamic and microscopic data exists for a wide range of temperatures for liquid rubidium and hence it represents a good test bed to challenge the SE relation with rising temperature from an experimental point of view. We performed classical molecular dynamics simulations to complement the existing experimental data using a pseudopotential, which describes perfectly the structure and dynamics of liquid rubidium. The derived SE relation from combining experimental shear viscosity data with simulated diffusion coefficients reveals a weak violation at about 1.3T_{melting}≈400 K. The microscopic relaxation dynamics on nearest neighbor distances from neutron spectroscopy demonstrate distinct changes in the amplitude with rising temperature. The derived average relaxation time for density fluctuations on this length scale shows a non-Arrhenius behavior, with a slope change around 1.5T_{melting}≈450 K. Combining the simulated macroscopic self-diffusion coefficient with that microscopic average relaxation time, a distinct violation of the SE relation in the same temperature range can be demonstrated. One can conclude that the changes in the collective dynamics, a mirror of the correlated movements of the particles, are at the origin for the violation of the SE relation. The changes in the dynamics can be understood as a transition from a more viscous liquid metal to a more fluid-like liquid above the crossover temperature range of 1.3-1.5 T_{melting}. The decay of the amplitude of density fluctuations in liquid aluminium, lead, and rubidium demonstrates a remarkable agreement and points to a universal thermal crossover in the dynamics of liquid metals.

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“…The conductivity in this composition is ionic and decreases as it approaches the critical point. The structure of alkali metals in solid and liquid states was investigated by Kietzmann et al, Ross et al, and Gómez et al [17][18][19] Significant progress in understanding the processes of metallization of alkali metal vapours occurred after the appearance of a series of works by Likalter. [20,21] Likalter suggested that in the near-critical region, the conductivity's crucial role will not be played by thermally ionized (free) electrons but by bound electrons, whose classically available orbitals begin to overlap.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The processes of thermal and “cold” ionization in caesium vapours

Хомкин

Шумихин

2021

Contributions to Plasma Physics

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The processes of thermal and "cold" ionization for the calculation of the composition and conductivity of near-critical caesium vapours are considered. The degrees of thermal and "cold" ionization are calculated for the near-critical region, and the temperature and density regions with predominant role of the processes of "cold" ionization are indicated. The conductivity of caesium vapours is calculated as the sum of the conductivities of thermal electrons and jellium electrons. The obtained results agree with the experimental data on the gas branch of the binodal and the near-critical isotherms. These facts can serve as confirmation of the proposed hypothesis about the existence of the jellium in the gas-plasma region and its coexistence with thermally ionized electrons.

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Structure of expanded fluid Rb and Cs: a quantum molecular dynamics study

Cited by 15 publications

References 35 publications

Complex Behavior of Fluid Lithium under Extreme Conditions

Complex Behavior of Fluid Lithium under Extreme Conditions

Stokes-Einstein relation of the liquid metal rubidium and its relationship to changes in the microscopic dynamics with increasing temperature

The processes of thermal and “cold” ionization in caesium vapours

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