Thermal Properties of the FCC Al3Zr : First-Principles Study

2010 ◽  
Vol 650 ◽  
pp. 313-319 ◽  
Author(s):  
Dong Lin Li ◽  
Ping Chen ◽  
Jian Xiong Yi ◽  
Bi Yu Tang ◽  
Li Ming Peng ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Thermal Properties ◽  
Bulk Modulus ◽  
Density Functional ◽  
Functional Theory ◽  
Density Functional Perturbation Theory ◽  
Wide Range ◽  
The Face ◽  
Ab Inito ◽  
Physical Quantities

Ab inito density functional theory (DFT) and density function perturbation theory (DFPT) have been applied to investigate the thermal properties of the face-center-cubic (fcc) Al3Zr alloy over a wide range of pressure and temperature. Phonon dispersions were obtained at equilibrium and strained configurations by density functional perturbation theory. Using the quasiharmonic approximation for the free energy, several interesting physical quantities such as thermal Grüneisen parameter, heat capacity at constant pressure and volume, thermal expansion coefficient and entropy, as well as adiabatic bulk modulus and isothermal bulk modulus, were calculated as a function of temperature and pressure, and the variation features of these quantities were discussed in details.

scholarly journals Electronic and thermal properties of LuNi2B2C under pressure

2020 ◽  
Vol 48 (5-6) ◽  
pp. 469-479
Author(s):  
LILI LIU ◽  
YUHAN JIANG ◽  
LIWAN CHEN ◽  
YOUCHANG JIANG ◽  
YELU HE ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Heat Capacity ◽  
Thermal Expansion ◽  
Perturbation Theory ◽  
Thermal Properties ◽  
Density Functional ◽  
Constant Pressure ◽  
Functional Theory ◽  
Density Functional Perturbation Theory ◽  
Temperature And Pressure

The electronic and thermal properties of LuNi2B2C were studied by performing density-functional theory (DFT) and density functional perturbation theory (DFPT). No virtual frequencies appear on the phonon spectrum, indicating that LuNi2B2C is dynamically stable in the tetragonal structure up to 30 GPa. The density of states at Fermi energy EF is nonzero and falls on the sharp peak, which is why LuNi2B2C has a high superconducting temperature. Moreover, the temperature and pressure dependences of bulk modulus, heat capacity at constant pressure and thermal expansion coefficient in a wide temperature (0-900 K) and pressure (0-30 GPa) ranges are presented in this study.

EXPLORING THE ADIABATIC CONNECTION BETWEEN WEAK- AND STRONG-INTERACTION LIMITS IN DENSITY FUNCTIONAL THEORY

2001 ◽  
Vol 15 (10n11) ◽  
pp. 1672-1683 ◽  
Author(s):  
JOHN P. PERDEW ◽  
STEFAN KURTH ◽  
MICHAEL SEIDL
Keyword(s):  
Perturbation Theory ◽  
Density Functional ◽  
Correlation Energy ◽  
Interaction Strength ◽  
Kcal Mole ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Density Functional Perturbation Theory ◽  
Simple Interaction

If the electron-electron repulsion in an atom or molecule were very weak, it could be treated by orbital-based perturbation theory. If this repulsion were very strong, it could be treated in a model of strict correlation. A simple interaction strength interpolation between these two limits, at fixed electron density, can describe the reality that lies between the extremes. By working entirely within a sophisticated density functional approximation, the meta-generalized gradient approximation, we find that the interpolation error is only about 0.1% for the exchange-correlation energy and about 4 kcal/mole = 0.17 eV for the atomization energy. We also find that real systems probably lie close to the radius of convergence of density functional perturbation theory.

A comparison study of the structural electronic, elastic and lattice dynamic properties of ZrInAu and ZrSnPt

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sinem Erden Gulebaglan ◽  
Emel Kilit Dogan
Keyword(s):  
Bulk Modulus ◽  
Band Gap ◽  
Density Functional ◽  
Dynamic Properties ◽  
Elastic Stiffness ◽  
Functional Theory ◽  
Density Functional Perturbation Theory ◽  
The Density Functional Theory ◽  
Indirect Band Gap ◽  
First Time

Abstract To estimate the structural, electronic, elastic and dynamic properties of ZrInAu and ZrSnPt compounds, the density functional theory within the general gradient approximation was used. The computed lattice parameters, bulk modulus and the derivation of bulk modulus with respect to pressure were displayed and compared with the theoretical result. The indirect band gap for ZrInAu was found to be 0.48 eV, and for ZrSnPt the indirect band gap was found as 1.01 eV. Elastic stiffness constants, bulk, shear and Young’s module, Poisson’s coefficients and Zener anisotropy factor are calculated. Elastic properties showed that the ZrSnPt compound is more durable than the ZrInAu compound. Phonon distribution curves and density of states were investigated using a density functional perturbation theory. Both ZrInAu and ZrSnPt compounds were demonstrated to be dynamically stable. The results of this study were obtained for the first time in the literature. These results will make an important contribution to the literature.

Structural, mechanical and thermal properties of Cu2ZnSiS4 with four structures from the first-principle calculations

2019 ◽  
Vol 33 (09) ◽  
pp. 1950067
Author(s):  
Yanli Gao ◽  
Yujing Dong
Keyword(s):  
Thermal Properties ◽  
Bulk Modulus ◽  
Elastic Constants ◽  
Density Functional ◽  
Debye Model ◽  
Energy Calculation ◽  
Mechanical And Thermal Properties ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Total Energy Calculation

In this paper, the structural, mechanical and thermal properties of the four structures of Cu2ZnSiS4 were studied on the basis of density functional theory (DFT). The generalized gradient approximation (GGA) of Perdew–Burke–Ernzerhof (PBE) was used to treat the exchange related energy and potential of total energy calculation. The independent elastic constants of the four structures are calculated, which prove that they are mechanically stable. The bulk modulus, Poisson’s ratios and universal anisotropy indices of Cu2ZnSiS4 can be calculated from the obtained elastic constants. In addition, the variation of the bulk modulus with the pressure (0–25 GPa) and temperature (0–700 K) have been reported. In order to further study the compound, the thermal properties of the compound were analyzed by using the quasi-harmonic Debye model, including specific heat, thermal expansion coefficient and Debye temperature.

Intrinsic Stacking Interactions of Natural and Artificial Nucleobases

2019 ◽  
Author(s):  
Drew P. Harding ◽  
Laura J. Kingsley ◽  
Glen Spraggon ◽  
Steven Wheeler
Keyword(s):  
Gas Phase ◽  
Electrostatic Interactions ◽  
Density Functional ◽  
Molecular Descriptors ◽  
Stacking Interactions ◽  
Interaction Energies ◽  
Functional Theory ◽  
Binding Partner ◽  
Heavy Atoms ◽  
Wide Range

The intrinsic (gas-phase) stacking energies of natural and artificial nucleobases were explored using density functional theory (DFT) and correlated ab initio methods. Ranking the stacking strength of natural nucleobase dimers revealed a preference in binding partner similar to that seen from experiments, namely G > C > A > T > U. Decomposition of these interaction energies using symmetry-adapted perturbation theory (SAPT) showed that these dispersion dominated interactions are modulated by electrostatics. Artificial nucleobases showed a similar stacking preference for natural nucleobases and were also modulated by electrostatic interactions. A robust predictive multivariate model was developed that quantitively predicts the maximum stacking interaction between natural and a wide range of artificial nucleobases using molecular descriptors based on computed electrostatic potentials (ESPs) and the number of heavy atoms. This model should find utility in designing artificial nucleobase analogs that exhibit stacking interactions comparable to those of natural nucleobases. Further analysis of the descriptors in this model unveil the origin of superior stacking abilities of certain nucleobases, including cytosine and guanine.

scholarly journals Solution-Processed OLEDs Based on Thermally Activated Delayed Fluorescence Copper(I) Complexes with Intraligand Charge-Transfer Excited State

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1125
Author(s):  
Teng Teng ◽  
Jinfan Xiong ◽  
Gang Cheng ◽  
Changjiang Zhou ◽  
Xialei Lv ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Functional Theory ◽  
Solution Processed ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Wide Range

A new series of tetrahedral heteroleptic copper(I) complexes exhibiting efficient thermally-activated delayed fluorescence (TADF) in green to orange electromagnetic spectral regions has been developed by using D-A type N^N ligand and P^P ligands. Their structures, electrochemical, photophysical, and electroluminescence properties have been characterized. The complexes exhibit high photoluminescence quantum yields (PLQYs) of up to 0.71 at room temperature in doped film and the lifetimes are in a wide range of 4.3–24.1 μs. Density functional theory (DFT) calculations on the complexes reveal the lowest-lying intraligand charge-transfer excited states that are localized on the N^N ligands. Solution-processed organic light emitting diodes (OLEDs) based on one of the new emitters show a maximum external quantum efficiency (EQE) of 7.96%.

Sign in / Sign up

Export Citation Format

Share Document