Ionization of molecules at the fluid–fluid phase transition in warm dense hydrogen

The problem of the fluid–fluid phase transition in warm dense hydrogen/deuterium has been studied experimentally and theoretically in the best laboratories in the last decade. However, the nature of the phase transition remains unclarified. In this paper we put forward the new idea that H₂ molecules are ionized at the phase transition to produce molecular H ₂ ⁺ and H ₃ ⁺ ions     

Metastable Conducting Crystalline Hydrogen at High Pressure

The quantum molecular dynamics method within the density functional theory has been used to calculate the equation of state, pair correlation function, and static electrical conductivity of solid hydrogen in the region of formation of a conducting phase. Hysteresis has been revealed on the density dependence of the pressure at a temperature of 100 K under compression and subsequent tension. The overlapping of branches of the isotherms of the molecular and nonmolecular phases of solid hydrogen corresponds to the region of existence of metastable states. The width of this region is 275 GPa. It has been shown that conducting crystalline nonmolecular hydrogen with P2₁/c symmetry can exist at extension to a pressure of 350 GPa.

     

Search for a ΔΔ(1236) component of the deuteron

The dp → nnpπ⁺, dp → ppnπ⁰ and dp → pppπ^- reactions at 3.33 GeV/c deuteron momentum on the proton target were studied in order to search for a ΔΔ configuration in the deuteron. The frequent backward emission of the (pπ⁺), (nπ^o) and (pπ^?) systems in the deuteron rest frame was observed. The origin of the effect was analysed from the point of view of a possible ΔΔ admixture in the deuteron wave function. Some other sources which may contribute to the signal are indicated.     

Semimetal States of Crystalline Molecular Hydrogen at High Pressures

JETP Letters - Semimetal states of crystalline molecular hydrogen have been obtained at a temperature of 100 K in the pressure range from 410 to 626 GPa. To analyze the nature of conductivity, the...     

Simulation of ab Initio Dynamics of the Formation of Metastable Conducting Solid Hydrogen

Journal of Experimental and Theoretical Physics - Density-functional theory (DFT) is applied to the calculation of the equation of state, the pair correlation function (PCF), and the static...     

Metastable molecular fluid hydrogen at high pressures

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 branches of pressure isotherms. This indicates the plasma nature of the phase transition.     

Structure and electromagnetic properties of hot-pressed La0.65Sr0.35Mn1 ? x Cr x O3 manganites under different synthesis conditions

The effect of hot pressing conditions on the characteristics of the crystalline and magnetic structures of Cr-doped lanthanum-strontium manganites has been investigated for the first time using X-ray diffraction, electron microscopy, magneto-optical visualization of magnetic flux, ferromagnetic resonance, and magnetic measurements. It is shown that application of pressure during sintering affects the concentration of differentvalence ions and structural vacancies and phase separation in the manganites studied. Original Russian Text ? N.A. Vybornov, F.D. Aliev, V.K. Karpasyuk, A.A. Pankratov, A.V. Saitov, V.V. Senin, S.G. Titova, L.S. Uspenskaya, 2008, published in Izvestiya Rossiiskoi Akademii Nauk. Seriya Fizicheskaya, 2008, Vol. 72, No. 10, pp. 1506–1509.     

Dynamics of the Structural Transformation of Crystalline Hydrogen upon the Transition into the Conductive State under Compression

Doklady Physics - 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...