Theoretical Study on Crystal Structure and Hydrogen Storage Properties of Sodium Hydride

2011 ◽  
Vol 287-290 ◽  
pp. 1348-1351
Author(s):  
Jie Hong Lei ◽  
Zheng Zhou Yan ◽  
Hao Duan ◽  
Yun Juan Zhang
Keyword(s):  
Crystal Structure ◽  
Hydrogen Storage ◽  
Density Functional ◽  
Sodium Hydride ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Hydrogen Storage Properties ◽  
Theoretical Results ◽  
Storage Properties ◽  
Good Agreement

In this paper, the crystal structure and hydrogen storage properties of the sodium hydride at different x value (NaHxD1-x, NaHxT1-x, NaDxT1-x; x=0, 0.25, 0.5, 0.75, 1.0) are investigated by using density functional theory within the generalized gradient approximation (GGA). The calculated results of NaH (D, T) are in good agreement with the other theoretical results. It has been found that, densities decreased with the increase of x value, while lattice parameters stay constant. The hydrogen storage properties of sodium hydride were predicted. The density-value x (ρ-x) relationship, the variations of the hydrogen storage properties with different crystal structure were obtained systematically.

scholarly journals Structural, Elastic, Electronic and Optical Properties of SrTMO3 (TM = Rh, Zr) Compounds: Insights from FP-LAPW Study

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2057 ◽  
Author(s):  
Areej Shawahni ◽  
Mohammed Abu-Jafar ◽  
Raed Jaradat ◽  
Tarik Ouahrani ◽  
Rabah Khenata ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Ultraviolet Region ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Lattice Constants ◽  
Far Ultraviolet ◽  
Theoretical Results ◽  
Good Agreement

The structural, mechanical, electronic and optical properties of SrTMO3 (TM = Rh, Zr) compounds are investigated by using first principle calculations based on density functional theory (DFT). The exchange-correlation potential was treated with the generalized gradient approximation (GGA) for the structural properties. Moreover, the modified Becke-Johnson (mBJ) approximation was also employed for the electronic properties. The calculated lattice constants are in good agreement with the available experimental and theoretical results. The elastic constants and their derived moduli reveal that SrRhO3 is ductile and SrZrO3 is brittle in nature. The band structure and the density of states calculations with mBJ-GGA predict a metallic nature for SrRhO3 and an insulating behavior for SrZrO3. The optical properties reveal that both SrRhO3 and SrZrO3 are suitable as wave reflectance compounds in the whole spectrum for SrRhO3 and in the far ultraviolet region (FUV) for SrZrO3.

Density functional theory (DFT) study of BaScO3H0.5 compound and its hydrogen storage properties

2019 ◽  
Vol 97 (11) ◽  
pp. 1191-1199 ◽  
Author(s):  
Aysenur Gencer ◽  
Gokhan Surucu
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Storage ◽  
Density Functional ◽  
Two Dimensions ◽  
Three Dimensions ◽  
Stable Phase ◽  
Partial Density ◽  
Functional Theory ◽  
Hydrogen Storage Properties ◽  
Storage Properties

BaScO3 and its hydride BaScO3H0.5 have been investigated using density functional theory (DFT) with the generalized gradient approximation (GGA). BaScO3 perovskite can crystallize in five possible crystal structures: orthorhombic (Pnma), tetragonal (P4mm), rhombohedral (R-3c), hexagonal (P63/mmc), and cubic (Pm-3m). These five possible phases have been optimized to obtain the most stable phase of BaScO3. The orthorhombic phase, being the most stable and having the lowest volume among the studied phases, has been considered for hydrogen bonding studies, and BaScO3H0.5 has been obtained. The electronic properties including band structure and corresponding partial density of states have been obtained for both BaScO3 and BaScO3H0.5 compounds. In addition, partial charge analysis has been performed. The calculated elastic constants have been used to obtain mechanical properties, such as bulk modulus, shear modulus, Young’s modulus, and Poisson’s ratio. Also, direction-dependent elastic properties have been studied in two dimensions and three dimensions. BaScO3 and BaScO3H0.5 compounds have ionic bonding and they are ductile materials. Moreover, the hydrogen storage properties of BaScO3H0.5 have been investigated and it is found that the gravimetric hydrogen storage capacity is 0.22 wt% and the hydrogen desorption temperature is determined as 1769.70 K.

IMPACT OF GEOMETRY ON THE HYDROGEN STORAGE PROPERTIES OF TITANIUM CARBIDE: A DFT STUDY ON THE MODEL TiC4H4

2007 ◽  
Vol 18 (12) ◽  
pp. 1951-1960
Author(s):  
OSMAN BARIŞ MALCIOĞLU ◽  
ŞAKİR ERKOÇ
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Storage ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Structural Geometry ◽  
Functional Theory ◽  
Hydrogen Storage Properties ◽  
Kubas Interaction ◽  
The Impact ◽  
Storage Properties

Transition metals such as titanium are known to attract (molecular) H 2 in some complexes through Kubas interaction. This interaction involves coordination of sigma bonds of the H2 with the transition metal, and it is comparatively strong, allowing promising hydrogen storage applications. In this work, the impact of structural geometry on this coordination is investigated using a model titan–carbide structure ( TiC 4 H 4) by performing density functional theory calculations.

Optical Properties of LaB6: A Computer Aided Simulation

2012 ◽  
Vol 571 ◽  
pp. 292-295
Author(s):  
Ben Hai Yu ◽  
Chao Xu ◽  
Dong Chen
Keyword(s):  
Optical Properties ◽  
Dielectric Function ◽  
Density Functional ◽  
Mechanical Stability ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Lattice Constants ◽  
The Density Functional Theory ◽  
Theoretical Results ◽  
Good Agreement

We report ab initio calculations of the structural, elastic and optical properties of the compound LaB6 as a function of pressure. The computation is based on the density functional theory in combination with the generalized gradient approximation functional. The calculated lattice constants and elastic moduli are compared with the theoretical results and a good agreement is found. LaB6 can retain its mechanical stability in the pressure range of 0-20GPa. Besides, the frequency-dependent dielectric function, absorption coefficient and loss function of LaB6 are also obtained. The calculated static dielectric function is 8.8 at 0GPa and 5GPa. The computed results should be testified by experiments.

First Principle Study of Hydrogen Storage

2013 ◽  
Vol 275-277 ◽  
pp. 2363-2366
Author(s):  
Bei Zhang ◽  
Jun Zhang ◽  
Chu Chen
Keyword(s):  
Hydrogen Storage ◽  
Density Functional ◽  
Dft Calculation ◽  
Metal Composite ◽  
Hydrogen Storage Capacity ◽  
Functional Theory ◽  
Ionic Polymer ◽  
Hydrogen Storage Properties ◽  
Polymer Metal ◽  
Storage Properties

The interactions between M and nH2O (M= Li+，Mg2+，Ca2+，and Al3+，n=1-8)had been investigated by using density-functional theory(DFT) calculation. We also discuss the interaction between ionic polymer-metal composite with different number of H2O and H2 (M:nH2O:2nH2). The results show that the hydrone could be greatly polarized, increasing the polarization of H2O and making the hydrogen storage properties become stronger. Our result is consistent with the experiment in that Mg2+ adsorbs three hydrones from the benzene ring which composes a stable structure, and the hydrogen storage capacity is up to 10 wt%.

Structural, Electronic and Elastic Properties of Neptunium Bismuthide (NpBi)

2016 ◽  
Vol 1141 ◽  
pp. 180-183
Author(s):  
Chandrabhan Makode ◽  
Mahendra Aynyas ◽  
Jagdeesh Pataiya ◽  
Archana Singh ◽  
Sankar P. Sanyal
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Functional Theory ◽  
Shear Moduli ◽  
Young’S Moduli ◽  
Theoretical Results ◽  
Good Agreement

The electronic, elastic and mechanical properties of neptunium bismuthide have been studied systematically using first principles density functional theory within generalized gradient approximation. Ground state properties such as lattice constant (a0), bulk modulus (B), its pressure derivative (B′) and elastic constants are calculated. The present results are in good agreement with the experimental and other available theoretical results. Poisson’s ratio (σ), Young’s moduli (E), shear moduli (GH) and the ratio of elastic anisotropy factor (A) are also estimated.

scholarly journals Solid-State and Theoretical Investigations of Some Banister-Type Macrocycles with 2,2’-Aldoxime-1,1’-Biphenyl Units

2021 ◽  
Vol 9 ◽  
Author(s):  
Ioan Stroia ◽  
Ionuţ -Tudor Moraru ◽  
Maria Miclăuş ◽  
Ion Grosu ◽  
Claudia Lar ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Density Functional ◽  
Alkali Metal Ions ◽  
Functional Theory ◽  
State Data ◽  
Supramolecular Associations ◽  
Theoretical Investigations ◽  
The Stability ◽  
Good Agreement

In the context of helical chirality, bridging of biphenyl units leads to banister-type compounds and the stability of the resulted atropisomers may increase dramatically if suitable changes are performed in the linker unit that coils around the biphenyl moiety. A rigorous density functional theory (DFT) study was conducted for macrocycles containing rigid oxime ether segments connected to the biphenyl backbone in order to determine how the rotation barriers are influenced by the presence of either a flexible oligoethyleneoxide or a more rigid m–xylylene component in the macrocycle. The calculated values for the racemization barrier were in good agreement with those obtained experimentally and confirm the benefit of introducing a more rigid unit in the macrocycle on the stability of atropisomers. Solid-state data were obtained and computed data were used to assess the contribution brought by supramolecular associations observed in the lattice to the stabilization of the crystal structure. Beside introducing rigidity in the linker, complexation of flexible macrocycles with alkali metal ions is also contributing to the stability of atropisomers, leading to values for the racemization barrier matching that of the rigid macrocycle. Using diethylammonium cation as guest for the macrocycle, a spectacular increase in the barrier to rotation was observed for the resulted pseudo[2]rotaxane.

scholarly journals Effect of Yb Concentration on the Structural, Magnetic and Optoelectronic Properties of Yb Doped ZnO: First Principles Calculation

2021 ◽  
Author(s):  
Mohamed Achehboune ◽  
Mohammed Khenfouch ◽  
Issam Boukhoubza ◽  
Issam Derkaoui ◽  
Bakang Moses Mothudi ◽  
...  
Keyword(s):  
Band Gap ◽  
Conduction Band ◽  
Density Functional ◽  
Blue Shift ◽  
First Principles Calculation ◽  
Theoretical Research ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Doped Zno ◽  
Good Agreement

Abstract Density functional theory-based investigation of the electronic, magnetic, and optical characteristics in pure and ytterbium (Yb) doped ZnO has been carried out by the plane-wave pseudopotential technique with generalized gradient approximation. The calculated lattice parameters and band gap of pure ZnO are in good agreement with the experimental results. The energy band-gap increases with the increase of Yb concentration. The Fermi level moves upward into the conduction band after doping with Yb, which shows the properties of an n-type se miconductor. New defects were created in the band-gap near the conduction band attributed to the Yb-4f states. The magnetic properties of ZnO were found to be affected by Yb doping; ferromagnetic property was observed for 4.17% Yb due to spin polarization of Yb-4f electrons. The calculated optical properties imply that Yb doped causes a blue shift of the absorption peaks, significantly enhances the absorption of the visible light, and the blue shift of the reflectivity spectrum was observed. Besides, a better transmittance of approximately 88% was observed for 4.17% Yb doped ZnO system. The refractive index and the extinction coefficient were observed to decrease as the Yb dopant concentration increased. As a result, we believe that our findings will be useful in understanding the doping impact in ZnO and will motivate further theoretical research.

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