Calculation of Dynamical Surface Properties of Noble-Gas Crystals. I. The Quasiharmonic Approximation

Allen, Roland E.; Wette, F. W. de

doi:10.1103/physrev.179.873

Cited by 208 publications

(80 citation statements)

References 19 publications

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“…29 If the explicit calculations of anharmonic phonon-phonon interaction coefficients remains a rather computationally demanding task, 30,31 with implementations often limited to a molecular, non-periodic context, 32-34 a simpler, though effective, approach for correcting most of the above mentioned deficiencies of the HA is represented by the so-called quasi-harmonic approximation (QHA), which retains the same formal expression of the harmonic Helmholtz free energy F and introduces the explicit dependence of phonon frequencies o kp on the volume. 35 Recent studies have highlighted the improved accuracy of quasi-harmonic calculations for thermal features of inorganic solids when use is made of suitable dispersion-corrected DFT methods. [36][37][38] In this Communication, we present a fully-integrated ab initio quantum-mechanical theoretical framework for the study of the…”

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confidence: 99%

Thermal properties of molecular crystals through dispersion-corrected quasi-harmonic ab initio calculations: the case of urea

2016

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An ab initio quantum-mechanical theoretical framework is presented to compute the thermal properties of molecular crystals. The present strategy combines dispersion-corrected density-functional-theory (DFT-D), harmonic phonon dispersion, quasi-harmonic approximation to the lattice dynamics for thermal expansion and thermodynamic functions, and quasi-static approximation for anisotropic thermoelasticity. The proposed scheme is shown to reliably describe thermal properties of the urea molecular crystal by a thorough comparison with experimental data.Molecular crystals have increasingly attracted great attention due to their peculiar chemical and physical properties, which make them suitable as high energy-density materials, 1-3 active pharmaceutical ingredients (APIs), 4-6 constituents of opto-electronic devices for their linear and non-linear optical properties, 7-9 etc.Nonetheless, from a theoretical view-point, they still represent a major challenge to the state-of-the-art quantum-chemical methods as many kinds of chemical interactions (covalent intra-molecular, electrostatic, hydrogen-bond, long-range dispersive) need to be accurately described simultaneously. Only in recent years, have different theoretical approaches been devised in order to predict their structural and energetic properties (with the main goal of discriminating between competing polymorphs): from force-field to high-level molecular fragment-based schemes, from periodic dispersion-corrected density functional theory (DFT-D) to periodic many-body wave-function techniques. [10][11][12][13][14][15][16][17][18] However, once a reliable and balanced description of the various chemical interactions has been achieved by means of any of the above-mentioned quantum-chemical methods, the extension of their applicability to more complex properties of technological and industrial relevance, which would greatly increase their predictiveness, such as mechanical, elastic, optical and thermodynamic responses, [19][20][21][22] has to be performed. Apart from the intrinsic high degree of complexity of the required theoretical techniques and algorithms, the main difficulty here is represented by the fact that most of those properties are largely affected by thermal effects, 23-25 even at room temperature, such as zero-point energy, harmonic and anharmonic thermal nuclear motion, thermal lattice expansion, etc.Most quantum-chemical ab initio methods describe the groundstate of a system at zero pressure and temperature. If the inclusion of pressure in the computed structural and elastic properties is a relatively easy task, 16,[26][27][28] this is definitely not the case when temperature has to be accurately accounted for. Indeed, we are still far from having effective schemes formally developed and efficiently implemented in a solid state context, particularly so when anharmonic terms to the lattice potential have to be included into the formalism. When the harmonic approximation (HA) to the lattice potential is used, the vibrational contribution to the free ene...

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Thermal properties of molecular crystals through dispersion-corrected quasi-harmonic ab initio calculations: the case of urea

2016

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“…16,17 In this respect, due to its formal simplicity and relatively low computational cost, an effective method of a) Electronic mail: alessandro.erba@unito.it choice is the so-called quasi-harmonic approximation (QHA), which introduces the missing volume dependence of phonon frequencies by retaining the harmonic expression for the Helmholtz free energy of the system. 18,19 A major advantage of such a scheme is that it allows for a natural combination of pressure and temperature on the same thermodynamic ground.…”

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confidence: 99%

Structural and elastic anisotropy of crystals at high pressures and temperatures from quantum mechanical methods: The case of Mg2SiO4 forsterite

Erba

Maul

Pierre

et al. 2015

The Journal of Chemical Physics

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Articles you may be interested inOn combining temperature and pressure effects on structural properties of crystals with standard ab initio techniques J. Chem. Phys. 141, 124115 (2014) We report accurate ab initio theoretical predictions of the elastic, seismic, and structural anisotropy of the orthorhombic Mg 2 SiO 4 forsterite crystal at high pressures (up to 20 GPa) and temperatures (up to its melting point, 2163 K), which constitute earth's upper mantle conditions. Single-crystal elastic stiffness constants are evaluated up to 20 GPa and their first-and second-order pressure derivatives reported. Christoffel's equation is solved at several pressures: directional seismic wave velocities and related properties (azimuthal and polarization seismic anisotropies) discussed. Thermal structural and average elastic properties, as computed within the quasi-harmonic approximation of the lattice potential, are predicted at high pressures and temperatures: directional thermal expansion coefficients, firstand second-order pressure derivatives of the isothermal bulk modulus, and P-V -T equation-of-state. The effect on computed properties of five different functionals, belonging to three different classes of approximations, of the density functional theory is explicitly investigated. C 2015 AIP Publishing LLC. [http://dx

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“…A recently developed fully-automated scheme, as implemented in a development version of the Crystal14 program [43], is used for performing quasi-harmonic calculations [44,45], which allows to go beyond the standard harmonic approximation to the lattice potential and to effectively compute the directional thermal lattice expansion, temperature dependence of the bulk modulus, difference between constant-pressure and constant-volume specific heats, adiabatic bulk modulus, etc. [46][47][48][49][50] In this respect, it is worth mentioning that a recent experimental study by Redfern et al [51] suggested CaSnO 3 to be highly quasi- Fig.…”

Section: Introductionmentioning

confidence: 99%

Thermal properties of the orthorhombic CaSnO3 perovskite under pressure from ab initio quasi-harmonic calculations

2016

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Structural, elastic and thermodynamic properties of the orthorhombic CaSnO 3 perovskite are theoretically investigated at the ab initio level as a function of temperature and pressure. Harmonic and quasiharmonic lattice dynamical calculations are performed with the Crystal program, by explicitly accounting for thermal expansion effects and by exploring the effect of several DFT functionals. The anisotropic, directional elastic response of the system is characterized up to 20 GPa of pressure. The thermal lattice expansion and elastic bulk modulus are described at simultaneous temperatures up to 2000 K and pressures up to 20 GPa. The Gibbs free energy of formation of CaSnO 3 from CaO and SnO 2 as a function of temperature is also addressed by means of fully-converged phonon dispersion calculations on the three systems.

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Calculation of Dynamical Surface Properties of Noble-Gas Crystals. I. The Quasiharmonic Approximation

Cited by 208 publications

References 19 publications

Thermal properties of molecular crystals through dispersion-corrected quasi-harmonic ab initio calculations: the case of urea

Thermal properties of molecular crystals through dispersion-corrected quasi-harmonic ab initio calculations: the case of urea

Structural and elastic anisotropy of crystals at high pressures and temperatures from quantum mechanical methods: The case of Mg2SiO4 forsterite

Thermal properties of the orthorhombic CaSnO3 perovskite under pressure from ab initio quasi-harmonic calculations

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