Hugoniot measurement of diamond under laser shock compression up to 2TPa

Abstract

A computationally efficacious free-energy functional for studies of inhomogeneous liquid water J. Chem. Phys. 137, 044107 (2012) Fourth virial coefficients of asymmetric nonadditive hard-disk mixtures J. Chem. Phys. 136, 184505 (2012) Equation of state and jamming density for equivalent bi-and polydisperse, smooth, hard sphere systems J. Chem. Phys. 136, 124508 (2012) On the theoretical determination of the Prigogine-Defay ratio in glass transition J. Chem. Phys. 136, 124502 (2012) Communication: Thermodynamics of condensed matter with strong pressure-energy correlations Hugoniot data of diamond was obtained using laser-driven shock waves in the terapascal range of 0.5-2 TPa. Strong shock waves were generated by direct irradiation of a 2.5 ns laser pulse on an Al driver plate. The shock wave velocities in diamond and Al were determined from optical measurements. Particle velocities and pressures were obtained using an impedance matching method and known Al Hugoniot. The obtained Hugoniot data of diamond does not show a marked difference from the extrapolations of the Pavlovskii Hugoniot data in the TPa range within experimental errors.

Multiphase equation of state for carbon addressing high pressures and temperatures

“…Comparison to recent laser-shock compression data [1][2][3][4][5] shows notable disagreement with the subset of results [1,4] which suggest that the principal Hugoniot is nearly coincident with the low-T isotherm even at pressures in excess of 1000 GPa. It is not at all clear at the moment as to what is causing such a discrepancy, particularly since the general features of our predictions (seen in Fig.…”

“…14). Also shown on this figure are data from static compression measurements of the room-temperature isotherm [82] (green circles at the lowest P ), magnetically driven flyer plate studies [8] (dense set of magenta + symbols with ρ ∼ 6-7 g/cc), and multiple sets of laser-shock data on the principal Hugoniot of diamond (symbols with error bars) [1][2][3][4][5]. Note that much of the highest-P Hugoniot data [1] seems to straddle the 300 K isotherm, even well above P = 1000 GPa; indeed, the data of Brygoo et al [4] even fall below our prediction of the room-T isotherm.…”

“…Recent laser-shock and ramp-compression studies [1][2][3][4][5][6][7], together with shock measurements performed with magnetically driven flyer plates [8], have produced data in the range from P = 0-50 Mbar. In addition, theoretical work on the EOS and phase diagram in this same range has yielded predictions which are largely (though not completely) in accord with these experimental data [8,9].…”

“…While satisfactory in a broad sense, this older EOS model suffers from three main drawbacks: (1) The embedding of the DFT-based 3-phase model into the coarsegrained model created kinks in the thermodynamic functions, even though an attempt was made to smooth out such features by interpolation. (2) There are no solid phases beyond BC8; sc and sh phases, for instance, are not included. (3) The electronic excitations of the high-T liquid are treated with an averageatom Thomas-Fermi model, so atomic shell structure is not included in sufficient detail.…”

Theoretical study of the porosity effects on the shock response of graphitic materials

“…The responses of carbon materials under high pressure and temperature constraints have motivated a large number of experimental and theoretical studies in the academic and applied physics fields [1][2][3][4][5][6][7][8][9]. However building accurate equations of state (EOS) remains a very challenging problem due to a lack of reliable experimental data on the thermal effects associated to its diverse forms and transformations: indeed temperature measurements can be particularly difficult under extreme, highly dynamic constraints.…”