Ab initio electronic, dynamic, and thermodynamic properties of isotopic lithium hydrides (6LiH, 6LiD, 6LiT, 7LiH, 7LiD, and 7LiT)

Zhang, H.F.; Yu, You; Zhao, Yanchong; Xue, Wenhui; Gao, Tao

doi:10.1016/j.jpcs.2010.03.037

Cited by 14 publications

(10 citation statements)

References 50 publications

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“…The agreement is generally good, considering that other sources of entropy can enter in the experimental values, with the exception of Be 2 C and GaN. The MARE between the theoretical and experimental values is 4.2%, in line with data present in literature 39,[56][57][58] , while the MAE is 2.23 J/(K mol) (9.6 × 10 −3 meV/(K atom)). Interestingly, at 300 K this is much smaller than the estimated error of other energy contributions for the estimation of phase stability 59 .…”

Section: B Thermodynamic Propertiessupporting

confidence: 87%

Convergence and pitfalls of density functional perturbation theory phonons calculations from a high-throughput perspective

Petretto

Gonze

Hautier

et al. 2018

Computational Materials Science

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The diffusion of large databases collecting different kind of material properties from highthroughput density functional theory calculations has opened new paths in the study of materials science thanks to data mining and machine learning techniques. Phonon calculations have already been employed successfully to predict materials properties and interpret experimental data, e.g. phase stability, ferroelectricity and Raman spectra, so their availability for a large set of materials will further increase the analytical and predictive power at hand. Moving to a larger scale with density functional perturbation calculations, however, requires the presence of a robust framework to handle this challenging task. In light of this, we automatized the phonon calculation and applied the result to the analysis of the convergence trends for several materials. This allowed to identify and tackle some common problems emerging in this kind of simulations and to lay out the basis to obtain reliable phonon band structures from high-throughput calculations, as well as optimizing the approach to standard phonon simulations.

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Section: B Thermodynamic Propertiessupporting

confidence: 87%

Convergence and pitfalls of density functional perturbation theory phonons calculations from a high-throughput perspective

Petretto

Gonze

Hautier

et al. 2018

Computational Materials Science

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“…If including the ZPE of harmonic phonons at the level of GGA and density-functional perturbation theory (DFPT), the B1-B2 phase transition pressure was predicted to be 308 GPa 19 . Using the plane-wave pseudopotential approach within the framework of DFT and DFPT, Zhang et al 22 discussed the electronic, lattice dynamic, and thermodynamic properties of AB (A = 6 Li, 7 Li; B = H, D, T) at ambient conditions. They confirmed that the lightest isotope 6 LiH has the largest zero-point motion in a harmonic approximation.…”

Section: Introductionmentioning

confidence: 99%

Compression and phase diagram of lithium hydrides at elevated pressures and temperatures by first-principles calculation

Chen¹,

Chen²,

Wu³

et al. 2016

J. Phys. D: Appl. Phys.

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High pressure and high temperature properties of AB (A = 6 Li, 7 Li; B = H, D, T) are investigated with first-principles method comprehensively. It is found that the H − sublattice features in the lowpressure electronic structure near the Fermi level of LiH are shifted to that dominated by the Li + sublattice in compression. The lattice dynamics is studied in quasi-harmonic approximation, from which the phonon contribution to the free energy and the isotopic effects are accurately modelled with the aid of a parameterized double-Debye model. The obtained equation of state (EOS) matches perfectly with available static experimental data. The calculated principal Hugoniot is also in accordance with that derived from shock wave experiments. Using the calculated principal Hugoniot and the previous theoretical melting curve, we predict a shock melting point at 56 GPa and 1923 K. In order to establish the phase diagram for LiH, the phase boundaries between the B1 and B2 solid phases are explored. The B1-B2-liquid triple point is determined at about 241GPa and 2413 K. The remarkable shift in the phase boundaries by isotopic effect and temperature reveal the significant role played by lattice vibrations. Furthermore, the Hugoniot of the staticdynamic coupling compression is assessed. Our EOS suggests that a precompression of the sample to 50 GPa will allow the shock Hugoniot passing through the triple point and entering the B2 solid phase. This transition leads to a discontinuity with 4.6% volume collapse, about four times greater than the same B1-B2 transition at zero temperature.PACS numbers: 63.20.dk, 64.60.A-, 64.70.D-As the lightest ionic compound, as well as the highest mass content of hydrogen and the highest melting point of 965 K at ambient pressure 1 in alkali metal hydrides, LiH has been widely studied and applied in the fields of hydrogen storage 2 , thermonuclear fusion, and aviation and space industries 3-6 . Early static compression experiment using diamond anvil cell (DAC) showed that LiH occupies an FCC lattice and orders in NaCl (B1) structure at ambient condition, and this structure is maintained up to at least 36 GPa (96 GPa for LiD) 7 . Under this pressure, all other alkali hydrides were observed to transform into CsCl (B2) phase (NaH at 29.3 GPa, KH at 4.0 GPa, RbH at 2.2 GPa, CsH at 0.83 GPa) 8-10 . However, the same structural transition in LiH has yet to be observed, which stimulates broad and continuous high pressure experimental and theoretical researches. Recently, by analyzing the x-ray diffraction (XRD) data obtained in DAC experiment 11 , it was shown that at room temperature LiH remains in the B1 structure under pressures up to 252 GPa, the highest pressure having been studied experimentally so far. In particular, the diffraction and Raman data indicated that the B1-B2 phase transition, as well as the accompanied metallization, may not be far beyond 252 GPa 11 .With theoretical methods, the pressure-induced B1-B2 structural transition and the insulator-metal transition in LiH at low temperat...

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“…An extensive amount of experimental and theoretical work has already been reported in past few decades 1-16 to understand their solid state properties. Many of these studies are also related to high pressure behavior of LiH, which include analysis of its phase stability, 1-10 determination of equation of state, 2,3,7-12 understanding the effect of pressure on electronic charge density, 12 band structure 8,12,13 and melting point 15 etc. As far as structural stability of this compound under high pressure is concerned, widely differing results have been reported in literature.…”

Section: Introductionmentioning

confidence: 99%

Thermo-physical properties of LiH at high pressures by ab initio calculations

Mukherjee

Sahoo

Joshi

et al. 2011

Journal of Applied Physics

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First principles calculations have been carried out to analyze structural stability and to determine the equation of state and elastic constants of LiH as a function of pressure. The comparison of total energies of B1 and B2 structures determined as a function of compression suggests the B1 ! B2 transition at $ 327 GPa. Various physical quantities including zero pressure equilibrium volume, bulk modulus, pressure derivative of bulk modulus, Debye temperature, bulk sound speed, Hugoniot parameter 's' and Gruneisen parameter have been derived. All these physical quantities compare well with the available experimental data. The single crystal elastic constants have been evaluated up to the B1!B2 transition pressure.

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Ab initio electronic, dynamic, and thermodynamic properties of isotopic lithium hydrides (6LiH, 6LiD, 6LiT, 7LiH, 7LiD, and 7LiT)

Cited by 14 publications

References 50 publications

Convergence and pitfalls of density functional perturbation theory phonons calculations from a high-throughput perspective

Convergence and pitfalls of density functional perturbation theory phonons calculations from a high-throughput perspective

Compression and phase diagram of lithium hydrides at elevated pressures and temperatures by first-principles calculation

Thermo-physical properties of LiH at high pressures by ab initio calculations

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