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Stanislav V. Sinogeikin

Bio: Stanislav V. Sinogeikin is an academic researcher from Carnegie Institution for Science. The author has contributed to research in topics: Elastic modulus & Brillouin Spectroscopy. The author has an hindex of 45, co-authored 143 publications receiving 5320 citations. Previous affiliations of Stanislav V. Sinogeikin include University of Illinois at Urbana–Champaign & Argonne National Laboratory.


Papers
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Journal ArticleDOI
TL;DR: Main features of the cell are an ultimate 90-degrees symmetrical axial opening and high stability, making the presented cell design suitable for a whole range of techniques from optical absorption to single-crystal X-ray diffraction studies, also in combination with external resistive or double-side laser heating.
Abstract: We present a new design of a universal diamond anvil cell, suitable for different kinds of experimental studies under high pressures. Main features of the cell are an ultimate 90-degrees symmetrical axial opening and high stability, making the presented cell design suitable for a whole range of techniques from optical absorption to single-crystal X-ray diffraction studies, also in combination with external resistive or double-side laser heating. Three examples of the cell applications are provided: a Brillouin scattering of neon, single-crystal X-ray diffraction of α-Cr(2)O(3), and resistivity measurements on the (Mg(0.60)Fe(0.40))(Si(0.63)Al(0.37))O(3) silicate perovskite.

258 citations

Journal ArticleDOI
TL;DR: The single-crystal elastic properties of synthetic pyrope and periclase (MgO) have been measured by Brillouin scattering in a diamond anvil cell (DAC) up to 20 GPa as discussed by the authors.

241 citations

Journal ArticleDOI
TL;DR: A tour-de-force study showed that as the pressure of lithium is increased to 50 GPa, its melting point drops to 190 GPa as mentioned in this paper, the lowest known melting point of any element.
Abstract: A tour-de-force study finds that as the pressure of lithium is increased to 50 GPa, its melting point drops to 190 K—the lowest yet observed of any elemental metal. The results suggest lithium could be a promising candidate for exploring exotic states of matter similar to that predicted for metallic hydrogen.

218 citations

Journal ArticleDOI
17 Aug 2012-Science
TL;DR: Using x-ray diffraction, Raman spectroscopy, and quantum molecular dynamics simulation, it is observed that, although carbon-60 cages were crushed and became amorphous, the solvent molecules remained intact, playing a crucial role in maintaining the long-range periodicity.
Abstract: Solid-state materials can be categorized by their structures into crystalline (having periodic translation symmetry), amorphous (no periodic and orientational symmetry), and quasi-crystalline (having orientational but not periodic translation symmetry) phases. Hybridization of crystalline and amorphous structures at the atomic level has not been experimentally observed. We report the discovery of a long-range ordered material constructed from units of amorphous carbon clusters that was synthesized by compressing solvated fullerenes. Using x-ray diffraction, Raman spectroscopy, and quantum molecular dynamics simulation, we observed that, although carbon-60 cages were crushed and became amorphous, the solvent molecules remained intact, playing a crucial role in maintaining the long-range periodicity. Once formed, the high-pressure phase is quenchable back to ambient conditions and is ultra-incompressible, with the ability to indent diamond.

157 citations

Journal ArticleDOI
TL;DR: In this paper, sound velocities and single-crystal elastic moduli of β phase (wadsleyite) and γ phase (ringwoodite) of (Mg,Fe)2SiO4 with Fe/(Fe+Mg) ratios of ∼0.075 and ∼ 0.09, respectively, have been determined at ambient conditions by Brillouin spectroscopy.
Abstract: The sound velocities and single-crystal elastic moduli of β phase (wadsleyite) and γ phase (ringwoodite) of (Mg,Fe)2SiO4 with Fe/(Fe+Mg) ratios of ∼0.075 and ∼0.09, respectively, have been determined at ambient conditions by Brillouin spectroscopy. Both compressional and shear wave aggregate velocities decrease with increasing Fe content in both phases, but the magnitude of this decrease is different for the two phases. The adiabatic bulk modulus, Ks, of Fe;-bearing β-Mg2SiO4 (Ks = 170±2 GPa) is indistinguishable from that of the Mg end-member within experimental uncertainty, whereas Ks of γ-(Mg,Fe)2SiO4 increases rapidly with increasing iron content. The shear moduli of both phases decrease with increasing Fe content. Our measurements indicate that the velocity and impedance contrasts between olivine and β-(Mg,Fe)2SiO4 are independent of Fe content for Mg-rich compositions, but the contrast for the β → γ-(Mg,Fe)2SiO4 transition increases significantly with increasing Fe content. The new data support a previous estimate of 40±10% for the olivine content of the upper mantle and suggest that less than 50% (Mg,Fe)2SiO4 is sufficient to account for the observed impedance contrasts at depths of both 410 km and 520 km. Unless the effect of Fe on elastic properties is accounted for, it is difficult to account for both the 410 and 520 km discontinuities with a single olivine content.

152 citations


Cited by
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01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

29,323 citations

Journal ArticleDOI
TL;DR: This paper focuses on descriptions of the implementation of CALYPSO code and why it works and testing of the code on many known and unknown systems shows high efficiency.

1,722 citations

Journal ArticleDOI
TL;DR: In this paper, the Tait equation of state (TEOS) was used to model the temperature dependence of both the thermal expansion and bulk modulus in a consistent way, which has led to improved fitting of the phase equilibrium experiments.
Abstract: The thermodynamic properties of 254 end-members, including 210 mineral end-members, 18 silicate liquid end-members and 26 aqueous fluid species are presented in a revised and updated internally consistent thermodynamic data set. The PVT properties of the data set phases are now based on a modified Tait equation of state (EOS) for the solids and the Pitzer & Sterner (1995) equation for gaseous components. Thermal expansion and compressibility are linked within the modified Tait EOS (TEOS) by a thermal pressure formulation using an Einstein temperature to model the temperature dependence of both the thermal expansion and bulk modulus in a consistent way. The new EOS has led to improved fitting of the phase equilibrium experiments. Many new end-members have been added, including several deep mantle phases and, for the first time, sulphur-bearing minerals. Silicate liquid end-members are in good agreement with both phase equilibrium experiments and measured heat of melting. The new dataset considerably enhances the capabilities for thermodynamic calculation on rocks, melts and aqueous fluids under crustal to deep mantle conditions. Implementations are already available in thermocalc to take advantage of the new data set and its methodologies, as illustrated by example calculations on sapphirine-bearing equilibria, sulphur-bearing equilibria and calculations to 300 kbar and 2000 °C to extend to lower mantle conditions.

1,651 citations

Journal ArticleDOI
TL;DR: In this paper, it was shown that the intrinsic correlation between hardness and elasticity of materials correctly predicts Vickers hardness for a wide variety of crystalline materials as well as bulk metallic glasses (BMGs).

1,632 citations

Journal ArticleDOI
TL;DR: On the bicentenary of the publication of Poisson's Traité de Mécanique, the continuing relevance of Poissons's ratio in the understanding of the mechanical characteristics of modern materials is reviewed.
Abstract: In comparing a material's resistance to distort under mechanical load rather than to alter in volume, Poisson's ratio offers the fundamental metric by which to compare the performance of any material when strained elastically. The numerical limits are set by ½ and -1, between which all stable isotropic materials are found. With new experiments, computational methods and routes to materials synthesis, we assess what Poisson's ratio means in the contemporary understanding of the mechanical characteristics of modern materials. Central to these recent advances, we emphasize the significance of relationships outside the elastic limit between Poisson's ratio and densification, connectivity, ductility and the toughness of solids; and their association with the dynamic properties of the liquids from which they were condensed and into which they melt.

1,625 citations