Equation of state of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn>7</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi mathvariant="normal">LiH</mml:mi></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn>7</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi mathvariant="normal">LiD</mml:mi></mml:math>from x-ray diffraction to 94 GPa

Loubeyre, P.; Toullec, R. Le; Hanfland, Michael; Ulivi, Lorenzo; Datchi, F.; Häusermann, Daniel M.

doi:10.1103/physrevb.57.10403

Cited by 67 publications

(84 citation statements)

References 19 publications

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“…Because of a significantly larger volume correction due to vibrational effects in ice VIII, we expect the calculated isotope shift to be Table I. numerically more robust at high P. A negative VIE is to be expected in a non-hydrogen-bonded system-for example, a value of À1% is measured for LiH [31]; therefore, the calculated negative VIE for ice VIII is a further indication of the weakening of hydrogen bonding at high pressure.…”

Section: -2mentioning

confidence: 99%

Dispersion Interactions and Vibrational Effects in Ice as a Function of Pressure: A First Principles Study

Murray

Galli

2012

Phys. Rev. Lett.

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We present a first principles theoretical framework that accurately accounts for several properties of ice, over a wide pressure range. In particular, we show that, by using a recently developed nonlocal van der Waals functional and by taking into account hydrogen zero point motion, one can properly describe the zero temperature equation of state, the vibrational spectra, and the dielectric properties of ice at low pressure and of ice VIII, a stable phase between 2 and 60 GPa. While semilocal density functionals yield a transition pressure from ice XI to VIII that is overestimated by almost an order of magnitude, we find good agreement with experiments when dispersion forces are taken into account. Zero point energy contributions do not alter the computed transition pressure, but they affect structural properties, including equilibrium volumes and bulk moduli. DOI: 10.1103/PhysRevLett.108.105502 PACS numbers: 63.20.dk, 62.50.Àp, 71.15.Mb, 83.80.Nb Ice has an extremely complex phase diagram [1] that has been studied for over a century [2], due to its importance in several disciplines, encompassing physics, chemistry, and earth and atmospheric sciences. However, until about 35 years ago, little was known experimentally about high pressure phases of ice. For example, the first characterization of ice VIII as an antiferroelectric, ordered phase-now known to be stable at low temperature between 2 and 60 GPa-appeared in 1976 [3]. From a theoretical standpoint, the description of the phase diagram and the properties of ice remains a very challenging problem. Recent ab initio calculations [4,5] have reported remarkable progress in describing the equations of state of some ice phases within density functional theory, as well as in computing optical spectra [6,7]. However, no first principles theory has yet successfully predicted with consistent accuracy a wide range of properties encompassing structural, vibrational, and dielectric properties over a broad range of pressures.In this Letter, we focus on ordered ice phases, ice XI, ordered cubic ice I c , and ice VIII. Ice XI and ordered I c are used as models of the stable phase of ice at ambient pressure close to 0 C. We show that a proper account both of dispersion forces and of hydrogen zero point motion are necessary to obtain a consistently accurate description of several properties of ice over a wide pressure range, at low temperature. We thus establish a theoretical framework that can be used to gain insight into the intricate physics of ice as a function of pressure, from first principles.We carried out calculations within density functional theory and compared results obtained with semilocal (PBE [8]) and nonlocal van der Waals (vdW-DF2 [9]) functionals. We used the QUANTUM ESPRESSO package [10] with hard norm-conserving pseudopotentials [11] for both hydrogen and oxygen and a plane-wave energy cutoff of 160 Ry. A 4 Â 4 Â 4 k-point grid was used for each structure.The lattice energies and equilibrium volumes of each phase were calculated by fully relaxing inte...

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Section: -2mentioning

confidence: 99%

Dispersion Interactions and Vibrational Effects in Ice as a Function of Pressure: A First Principles Study

Murray

Galli

2012

Phys. Rev. Lett.

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“…The calculated 300 K static EOS for the B1 phase is compared with the experimental data [1,7] in Fig. 1.…”

Section: Calculational Detailsmentioning

confidence: 99%

LiH under high pressure and high temperature: A first‐principles study

Wang

Ahuja

Johansson

2003

Physica Status Solidi (b)

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“…7. ªÊÑÕÇÓÏÞ ÔÉÂÕËâ AEÎâ LiH Ë LiD ÒÓË ÍÑÏÐÂÕÐÑÌ ÕÇÏÒÇÓÂÕÖÓÇ ÒÑ AEÂÐÐÞÏ [22]. £ÇÎËÚËÐÂ DPaK DVaV VLiH À VLiDaVLiD ÓÂÔÔÚËÕÂÐÂ ËÊ AEÂÐÐÞØ [22]. …”

Section: ±îâäîçðëç°ãunclassified

Quantum effects in condensed matter at high pressure

Стишов¹

2001

Uspekhi Fizicheskikh Nauk

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2.¯ÇÏÐÑÅÑ ËÔÕÑÓËË©ÂÒËÛÇÏ ÒÑÎÐÖá àÐÇÓÅËá E t Ë AEÂÄÎÇÐËÇ P ÒÓÑËÊÄÑÎß-ÐÑÌ ÔËÔÕÇÏÞ ÒÓË T 0 Ä ÄËAEÇ"¬ÄÂÐÕÑÄÑÇ" AEÂÄÎÇÐËÇ P z ÒÑ ÒÑÓâAEÍÖ ÄÇÎËÚËÐÞ ÓÂÄÐÑ ÒÎÑÕÐÑÔÕË ÐÖÎÇÄÑÌ àÐÇÓÅËË E z , ËÎË ¦ÔÎË ÍÄÂÐÕÑÄÞÇ à××ÇÍÕÞ ÏÂÎÞ 4 , ÕÑ, ËÔÒÑÎßÊÖâ ÕÓËÄËÂÎß-ÐÑÇ ÔÑÑÕÐÑÛÇÐËÇ P z KDVaV, ÒÑÎÖÚËÏ:£ ÍÄÂÊËÅÂÓÏÑÐËÚÇÔÍÑÏ ÒÓËÃÎËÉÇÐËË ¤ÓáÐÂÌÊÇÐÂ ÔÑÑÕÐÑÛÇÐËâÏ (8) Ë (9) ÏÑÉÐÑ ÒÓËAEÂÕß ÍÑÎËÚÇÔÕÄÇÐÐÖá ×ÑÓÏÖ, ÒÇÓÇÒËÔÂÄ ËØ Ä ÄËAEÇ (10) Ë (12).¯ÇÕÓÖAEÐÑ ÕÂÍÉÇ ÐÂÒËÔÂÕß ÔÑÑÕÄÇÕÔÕÄÖáÜÇÇ ÄÞÓÂÉÇÐËÇ AEÎâ ÏÑAEÖÎâ ÑÃÝÇÏÐÑÌ ÖÒÓÖÅÑÔÕË (11): ªÐAEÇÍÔÞ m Ë n Ä ÔÑÑÕÐÑÛÇÐËâØ (13) ªÊ (13) Experimental data on the inêuence of quantum effects on the equation of state and melting at high pressure are reviewed. It is shown that quantum isotopic effects tend to increase upon compression of substances with predominately Coulomb interaction, whereas compression of the van der Waals substances reveals the opposite trend. The`cold' melting of`Coulomb' substances at high pressure is discussed.

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Equation of state of7LiHand7LiDfrom x-ray diffraction to 94 GPa

Cited by 67 publications

References 19 publications

Dispersion Interactions and Vibrational Effects in Ice as a Function of Pressure: A First Principles Study

Dispersion Interactions and Vibrational Effects in Ice as a Function of Pressure: A First Principles Study

LiH under high pressure and high temperature: A first‐principles study

Quantum effects in condensed matter at high pressure

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