Plasma‐Plasma and Liquid‐Liquid First‐Order Phase Transitions

Norman, G. É.; Saitov, I. M.; Stegaĭlov, V. V.

doi:10.1002/ctpp.201400088

Cited by 24 publications

(6 citation statements)

References 61 publications

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“…1, pathway I) or increasing temperature to cross the plasma phase transition (Fig. 1, pathway II) (12)(13)(14)(15)(16)(17). Pathway I transitions through a number of phases not envisioned in the simple phase diagram predicted by WH.…”

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confidence: 99%

Observation of the Wigner-Huntington transition to metallic hydrogen

Dias

Silvera

2017

Science

510

331

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Producing metallic hydrogen has been a great challenge in condensed matter physics. Metallic hydrogen may be a room-temperature superconductor and metastable when the pressure is released and could have an important impact on energy and rocketry. We have studied solid molecular hydrogen under pressure at low temperatures. At a pressure of 495 gigapascals, hydrogen becomes metallic, with reflectivity as high as 0.91. We fit the reflectance using a Drude free-electron model to determine the plasma frequency of 32.5 ± 2.1 electron volts at a temperature of 5.5 kelvin, with a corresponding electron carrier density of 7.7 ± 1.1 × 10 particles per cubic centimeter, which is consistent with theoretical estimates of the atomic density. The properties are those of an atomic metal. We have produced the Wigner-Huntington dissociative transition to atomic metallic hydrogen in the laboratory.

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confidence: 99%

Observation of the Wigner-Huntington transition to metallic hydrogen

Dias

Silvera

2017

Science

510

331

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“…We have used our QMD+KG values on 1 DC and K to calculate the Lorenz number according to Equation (18). Figure 5 shows the temperature dependence of L. It can be seen that the Wiedemann-Franz law fails: the L values do not coincide with L id , and L(T) is not even constant.…”

Section: Resultsmentioning

confidence: 99%

“…Methods based on quantum molecular dynamics (QMD) and the Kubo-Greenwood (KG) formula are well suited for these conditions. Recent QMD+KG calculations have addressed the properties of hydrogen, [18] xenon, [19,20] copper, [21] and plastics. [14] Transport and optical properties may be obtained if QMD is used together with the KG formula (QMD+KG).…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic, transport, and optical properties of dense silver plasma calculated using the GreeKuP code

Knyazev

Levashov

2018

Contributions to Plasma Physics

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The transport and optical properties of a dense silver plasma are calculated using our parallel GreeKuP code. The code uses the results of Vienna ab initio simulation package (VASP) as input information and is based upon the Kubo-Greenwood formula. The calculation is performed at the normal density 10.5 g/cm 3 and 3 kK ≤ T ≤ 20 kK. Under these conditions, the results are strongly influenced by the presence of the d-electrons in silver: the real part of dynamic electrical conductivity has a non-Drude shape, the temperature dependence of thermal conductivity is non-monotonic, and the Wiedemann-Franz law is violated. KEYWORDSGreeKuP code, Kubo-Greenwood formula, quantum molecular dynamics, transport and optical properties 1 2 COMPUTATIONAL TECHNIQUEOnly some of the issues concerning the computation technique will be discussed here. For more detailed descriptions, one may refer to our earlier paper [23] and earlier works. [16,17] Contrib. Plasma Phys.

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“…Initially, the transition of fluid hydrogen from the molecular state to the atomic state was considered from the point of view of chemical models [23–36] . The concept of plasma phase transition was introduced [23,37,38] . Later, the insulator‐to‐metal transition concept has become widespread [39] .…”

Section: Introductionmentioning

confidence: 99%

Exciton Nature of Plasma Phase Transition in Warm Dense Fluid Hydrogen: ROKS Simulation**

Fedorov

Stegaĭlov

2022

ChemPhysChem

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The transition of warm dense fluid hydrogen from an insulator to a conducting state at pressures of about 20–400 GPa and temperatures of 500–5000 K has been the subject of active scientific research over the past few decades. However, various experimental and theoretical methods do not provide consistent results. In this work, we have applied the restricted open‐shell Kohn–Sham (ROKS) method for first principles molecular dynamics of dense hydrogen after thermal excitation to the first singlet excited state. The Wannier localization method has allowed us to analyze the exciton dynamics in this system. The model shows that a key mechanism of the transition is associated with the dissociation of electron‐hole pairs, which allows explaining several stages of the transition of fluid H2 from molecular state to plasma. This mechanism is able to give a quantitative description of several experimental results as well as to resolve the discrepancies between experimental studies.

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Plasma‐Plasma and Liquid‐Liquid First‐Order Phase Transitions

Cited by 24 publications

References 61 publications

Observation of the Wigner-Huntington transition to metallic hydrogen

Observation of the Wigner-Huntington transition to metallic hydrogen

Thermodynamic, transport, and optical properties of dense silver plasma calculated using the GreeKuP code

Exciton Nature of Plasma Phase Transition in Warm Dense Fluid Hydrogen: ROKS Simulation**

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