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## Metastable states of fluid–fluid phase transition in warm dense hydrogen

Journal of Physics: Conference Series. 2019. Vol. 1147. No. 012003. P. 1-6.

The warm dense hydrogen is studied by means of the ab initio molecular dynamics

simulation in the region of fluid–fluid phase transition. The metastable states of two isotherm

of 700 and 1000 K are calculated. The metastable ranges by pressure are 470 and 320 kbar

respectively. The existence of metastability is a strong criterion that the transition is a first

order phase transition.

Norman G., Saitov I., Sartan R., Contributions to Plasma Physics 2019 Vol. 59 No. 6 P. e201800173

Warm dense hydrogen is studied in the region of fluid–fluid phase transition within
the framework of the density functional theory. We report a procedure of obtaining
metastable states and calculate the equation of state. Metastable states are diagnosed by pair correlation functions and values of conductivity. We obtain a strong
overlapping through the density of metastable and equilibrium ...

Added: October 30, 2019

Norman G., Saitov I., Доклады Российской академии наук. Физика, технические науки (ранее - Доклады Академии Наук. Физика) 2017 Т. 474 № 6 С. 687-691

The density functional theory is used to calculate the equation of state and the proton-proton pair correlation functions in the range of hydrogen temperatures and densities where the fluid-fluid-phase transition is expected. The metastable states are considered. The critical temperature has been estimated to be ~4000 K. We propose a two-step mechanism: the partial ionization ...

Added: December 2, 2017

Stegailov V., Zhilyaev P. A., Contributions to Plasma Physics 2015 Vol. 55 No. 2-3 P. 164-171

Non-equilibrium two-temperature warm dense metals consist of the ion subsystem that is subjected to structural transitions and involved in the mass transfer, and the electron subsystem that in various pulsed experiments absorbs energy and then evolves together with ions to equilibrium. Definition of pressure in such non-equilibrium systems causes certain controversy. In this work we ...

Added: March 15, 2017

Saitov I., Molecular Physics 2016 Vol. 114 No. 3-4 P. 446-452

Density functional theory (DFT) is applied for the calculation of the dielectric function (DF), reflectivity,
conductivity, plasma frequency and effective free electron density of warm dense matter
(WDM). Shock-compressed xenon plasma and warm dense hydrogen are considered. The longitudinal
expression in the long wavelength limit is applied for the calculation of the imaginary part of
the DF. The real ...

Added: March 30, 2017

Ofengeim D., Physical Review D - Particles, Fields, Gravitation and Cosmology 2020 Vol. 101 No. 10 P. 103029

I have demonstrated the existence of a tight correlation between the mass, radius, central density, and pressure of maximum-mass neutron stars modeled using diverse baryonic equations of state. A possible explanation for these correlations is provided. Simple analytic forms of such correlations are suggested and compared with observational constraints on the maximum mass of neutron ...

Added: November 11, 2020

Norman G., Saitov I., Stegailov V. et al., Contributions to Plasma Physics 2013 Vol. 53 No. 4-5 P. 300-310

Warm dense matter conductivity and reflectivity are investigated by means of density functional theory. Both one- and two-temperature cases are considered. One-temperature mode is related to equilibrium state where temperature of electrons and ions are equal. As an example of one-temperature system xenon plasma is studied. The reflectivity of shock-compressed dense xenon plasma is calculated ...

Added: March 19, 2014

Быстрый Р.Г., Лавриненко Я. С., Ланкин А. В. et al., Теплофизика высоких температур 2014 Т. 52 № 4 С. 494-503

Pressure fluctuations in equilibrium nonideal plasma are investigated by the method of classical molecular dynamics. Examples of plasma parameters at which the pressure fluctuation distribution function is not normal but can be approximated by the sum of two normal distributions were found. The electron-ion interaction is described by the Coulomb potential cutoff at the depth ...

Added: December 25, 2014

Norman G., Saitov I., Успехи физических наук 2021 Т. 191 № 11 С. 1153-1186

Recently developed experimental methods for the generation and diagnostics of nonideal plasma and warm dense
matter are reviewed. Modern theoretical methods applied to solve the problem of fluid±fluid phase transitions, including the plasma phase transition, are considered. Quantum simulation methods and the results obtained in the chemical model of plasma are analyzed. Particular attention is paid ...

Added: October 29, 2022

Bugaev K. A., Yakovenko N. S., Oliinyk P. V. et al., Physica Scripta 2021 Vol. 96 No. 12 Article 125302

An analytical formula that accurately accounts for the Lorentz contraction of the excluded volume of two relativistic hadrons with hard-core repulsion is worked out. Using the obtained expression we heuristically derive the equation of state of Boltzmann particles with relativistic excluded volumes in terms of system pressure and its surface and curvature tension coefficients. The ...

Added: January 12, 2023

Комаров Н. С., Physical Chemistry Chemical Physics 2021 Vol. 23 P. 1896-1913

We use a traditional surface science approach to create and study an atomically thin NiI2 film (a promising two-dimensional ferromagnetic material) formed on nickel substrate as a result of molecular iodine adsorption. The I/Ni(100) system was examined with scanning tunneling microscopy (STM), low energy electron diffraction (LEED) and density functional theory calculations. We found out that ...

Added: January 21, 2021

Norman G., Saitov I., Journal of Physics: Conference Series 2016 Vol. 774 No. 012015 P. 1-8

An analysis is presented of experimental data where fluid–fluid phase transitions are observed for different substances at high temperatures with triple points on melting curves. Viscosity drops point to the structural character of the transition, whereas conductivity jumps remind of both semiconductor-to-metal and plasma nature. The slope of the phase equilibrium dependencies of pressure on ...

Added: March 30, 2017

Stegailov V., Zhilyaev P., Molecular Physics 2016 Vol. 114 No. 3-4 P. 509-518

Warm dense matter is a peculiar state with solid densities and temperatures 1 − 100 eV. Its ab initio description waits united efforts of quantum chemistry, condensed matter and plasma physics. We use the finite temperature Kohn–Sham density functional theory (a ‘workhorse’ in this field) to study the pressure build-up with increase of electronic temperature in ...

Added: July 5, 2016

Sinitsa A., Lebedeva I., Polynskaya Y. et al., Physical Chemistry Chemical Physics 2021 Vol. 23 No. 1 P. 425-441

Molecular dynamics simulations show that a graphene nanoribbon with alternating regions which are one and three hexagons wide can transform into a hybrid 1D nanoobject with alternating double chains and polycyclic regions under electron irradiation in HRTEM. A scheme of synthesis of such a nanoribbon using Ullmann coupling and dehydrogenation reactions is proposed. The reactive ...

Added: June 20, 2021

Polynskaya Y., Sinitsa A., Vyrko S. et al., Physica E: Low-Dimensional Systems and Nanostructures 2023 Vol. 148 P. 1-7

Possible mechanism of cap expansion of preliminarily prepared carbon nanotube is proposed and confirmed by DFT calculations. According to this mechanism single carbon atoms adsorbed on lateral surface of the nanotube (sp atoms) migrate along the nanotube and are trapped at its cap in the potential well. When pair of sp atoms meet at the ...

Added: August 23, 2023

Norman G., Saitov I., Contributions to Plasma Physics 2019 Vol. 59 No. 6 P. e201800182

At first, we present a brief review of the problem. Then, we consider plasma phase transition (PPT) as a mechanism of the first order fluid–fluid phase transition in warm dense hydrogen. The pros and cons are analysed. The properties of warm dense hydrogen are investigated by ab initio methods of molecular dynamics using the density ...

Added: October 30, 2019

49606783, Russian Journal of Mathematical Physics 2015 Vol. 22 No. 1 P. 53-67

We provide a detailed explanation of the physical meaning of some concepts used in the new statistics corresponding to thermodynamics, including the notions of locally ideal gas, number of collective degrees of freedom, and jamming factor. The equation of state is treated as a surface in three-dimensional space, and the spinodal is viewed as an ...

Added: March 8, 2015

Norman G., Saitov I., Doklady Physics 2019 Vol. 64 No. 4 P. 145-149

—The structural transformation of solid hydrogen under compression along the isotherm of 100 K in
the region of transition into the conductive state was studied within the density functional theory. The pressure, the pair correlation function of protons, the density of electron states, and the electrical conductivity were calculated within a range of hydrogen densities from ...

Added: October 30, 2019

Zhilyaev P., Norman G., Stegailov V., Doklady Physics 2013 Vol. 58 No. 8 P. 334-338

Warm dense matter (WDM) is a state of a substance with a solid-state density and temperature from 1 to 100 eV. Researchers believe that such a state exists in the cores of giant planets. Investigation of WDM is important for some applications, such as surface treatment on the nanometer scale, laser ablation, and the formation ...

Added: March 19, 2014

Norman G., Saitov I., Journal of Physics: Conference Series 2019 Vol. 1147 No. 012002 P. 1-4

The density functional theory is applied for the calculation of the dependence of
pressure and profiles of proton–proton pair correlation function of hydrogen on density in the
range 1.14–2.0 g/cm3 at temperature 100 K. The calculated range of pressures is 300–2600 GPa,
which corresponds to the solid phase of hydrogen. The transition at pressure 607 GPa is found,
which ...

Added: October 30, 2019

Norman G., Pisarev V., Fleita D., Письма в Журнал экспериментальной и теоретической физики 2019 Т. 109 № 10 С. 689-693

Equilibrium and metastable states of a liquid are studied near the liquid-crystal phase transition point in a metallic melt using a time-dependent four-point correlation function. This function was proposed earlier for revealing the collective atomic motion in equilibrium liquids. The characteristic changes in the behavior of liquid when it passes to the region of metastability ...

Added: February 13, 2020

Malova H. V., V. Yu. Popov, Grigorenko E. E. et al., Astrophysical Journal 2017 Vol. 834 No. 34 P. 1-9

We investigate quasi-adiabatic dynamics of charged particles in strong current sheets (SCSs) in the solar wind, including the heliospheric current sheet (HCS), both theoretically and observationally. A self-consistent hybrid model of an SCS is developed in which ion dynamics is described at the quasi-adiabatic approximation, while the electrons are assumed to be magnetized, and their ...

Added: February 15, 2017

Fleita D., Norman G., Pisarev V., Journal of Physics: Condensed Matter 2020 Vol. 32 No. 21 P. 214009

The previously discovered features of the temperature behaviour of four-point spatial correlators allow us to study transitions to metastable states. Similar integral characteristics simultaneously study microscopic effects (vortex formation and clustering) and the effect of these phenomena on the thermodynamics of the whole system. It is shown that spatial and temporal behaviour of correlators in ...

Added: February 18, 2020

Norman G., Saitov I., Stegailov V. et al., Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 2015 Vol. 91 No. 023105 P. 1-10

Reflectivity of shocked compressed xenon plasma is calculated within the framework of the density functional theory approach. Dependencies on the frequency of incident radiation and on the plasma density are analyzed. The Fresnel formula for the reflectivity is used. The longitudinal expression in the long-wavelength limit is applied for the calculation of the imaginary part ...

Added: March 15, 2017

Stolyarov V., Pons S., Vlaic S. et al., The Journal of Physical Chemistry Letters 2021 Vol. 12 No. 37 P. 9068-9075

We report on structural and electronic properties of superconducting nanohybrids made of Pb grown in the ultrahigh vacuum on the atomically clean surface of single crystals of topological Bi2Te3. In situ scanning tunneling microscopy and spectroscopy demonstrated that the resulting network is composed of Pb-nanoislands dispersed on the surface and linked together by an amorphous ...

Added: October 18, 2021