Structures and electronic properties of WmCunH2 (m+n ≤ 7) clusters

2018 ◽  
Vol 32 (20) ◽  
pp. 1850209
Author(s):  
Zhicheng Yu ◽  
Xiurong Zhang ◽  
Kun Gao ◽  
Peiying Huo
Keyword(s):  
Hydrogen Storage ◽  
Electronic Properties ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Generalized Gradient ◽  
Functional Theory ◽  
High Thermodynamic Stability ◽  
Analysis Of Stability ◽  
Ground State Structures ◽  
Adsorption And Dissociation

Geometric and electronic structures of W[Formula: see text]Cu[Formula: see text]H2 (m + n [Formula: see text] 7) clusters have been systematically calculated by density functional theory (DFT) at the generalized gradient approximation (GGA) level for ground-state structures. For all W–Cu clusters, H atoms prefer to attach to W atoms in this system during adsorption. And more electrons transfer from H atom to W atom with the growth of the size of the cluster which benefits the hydrogen storage. Analysis of stability properties and electronic properties shows that hydrogen adsorption and dissociation process take place more efficiently at the W2Cu3H2 cluster than the others. Due to high thermodynamic stability and adsorption energy of W5CuH2 cluster among W[Formula: see text]Cu[Formula: see text]H2 (m + n [Formula: see text] 7) clusters, W5Cu is more suitable for hydrogen storage.

STRUCTURE STABILITY AND ELECTRONIC PROPERTIES OF CumConCO (m+n=2–7) CLUSTERS

2016 ◽  
Vol 24 (04) ◽  
pp. 1750049 ◽  
Author(s):  
JUN ZHU ◽  
XIU-RONG ZHANG ◽  
PEI-YING HUO ◽  
ZHI-CHENG YU
Keyword(s):  
Electronic Properties ◽  
Ground State ◽  
Density Functional ◽  
Adsorption Process ◽  
Magnetic Moments ◽  
Structure Stability ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Adsorption Energies ◽  
Ground State Structures

The structure stability and electronic properties of CumConCO ([Formula: see text]–7) clusters have been systematically investigated using density functional theory (DFT) within the generalized gradient approximation (GGA). The results indicate that the ground state structures of CumConCO clusters obtained by adsorbing CO molecules on the top sites of stable CumConclusters with C atoms and CO molecules have been activated during adsorption process. Cu2CO, CuCoCO, Cu3CoCO, Co4CO, Cu4CoCO and Cu3Co3CO clusters are stronger than other ground state clusters in thermodynamic stability. Cu2CO, Cu4CO and Cu6CO clusters show stronger chemical stability; Co2CO, Co4CO, Cu5CoCO, Cu3Co3CO, Cu2Co5CO and Co7CO clusters show better propensity to adsorb CO for these clusters have larger adsorption energies; Electronic states of Cu2Co3CO, CuCo4CO, Co5CO, Cu4Co3CO, Cu3Co4CO, CuCo6CO and Co7CO clusters are mainly influenced by those of 3d orbitals in Co and Cu atoms, the contribution to total magnetic moments of these clusters comes mainly from Co atoms and these clusters have high magnetism.

scholarly journals Electronic Properties of Hydrogenated Hexagonal Boron Nitride (h-BN): DFT Study

2019 ◽  
Vol 4 (2) ◽  
pp. 72-79
Author(s):  
B. Chettri ◽  
P. K. Patra ◽  
Sunita Srivastava ◽  
Lalhriatzuala ◽  
Lalthakimi Zadeng ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Band Gap ◽  
Electronic Properties ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Hexagonal Boron Nitride ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
The Density Functional Theory

In this work, we have constructed the hydrogenated hexagonal boron nitride (h-BN) by placing hydrogen atom at different surface sites. The possibility of hydrogen adsorption on the BN surface has been estimated by calculating the adsorption energy. The electronic properties were calculated for different hydrogenated BNs. The theoretical calculation was based on the Density Functional Theory (DFT). The electron-exchange energy was treated within the most conventional functional called generalized gradient approximation. The calculated band gap of pure BN is 3.80 eV. The adsorption of two H-atoms at two symmetrical sites of B and N sites reduces the band gap value to 3.5 eV. However, in all other combination the systems show dispersed band at the Fermi level exhibiting conducting behavior. Moreover, from the analysis of band structure and Density Of States we can conclude that, the hydrogenation tunes the band gap of hexagonal boron nitride.

Hydrogen storage on multiple palladium-decorated graphene

2021 ◽  
Author(s):  
Saran Lamichhane ◽  
Nurapati Pantha ◽  
Bipin Khatry ◽  
Prakash Parajuli ◽  
Narayan Prasad Adhikari
Keyword(s):  
Hydrogen Storage ◽  
First Principles ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Magnetic Characteristics ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Symmetry Break

The geometries, structural stability, electrical and magnetic characteristics of pure and multiple palladium (Pd)-adsorbed graphene, followed by hydrogen adsorption, are investigated using first-principles calculations with the density functional theory. In the DFT-D2 technique, first-principles computations with the van der Waals interaction are done using the generalized gradient approximation. In a [Formula: see text] supercell, the adsorption energy per Pd atom is found to be 1.20 eV in the optimal adsorption shape. The bandgap of 51 meV has opened in multiple Pd-decorated graphene, according to band calculations. This band’s opening is ascribed to a symmetry break. The binding energy for hydrogen adsorption in optimal double Pd-decorated graphene was determined to be in the range of (0.14–0.73) eV per hydrogen molecule, indicating that Pd-decorated graphene might be used as a hydrogen storage material.

STRUCTURE AND MAGNETIC PROPERTIES OF Co12X(X = Ni, Ag, Pt, Au) CLUSTERS

2007 ◽  
Vol 21 (30) ◽  
pp. 5091-5098 ◽  
Author(s):  
Q. L. LU ◽  
J. C. JIANG ◽  
J. G. WAN ◽  
G. H. WANG
Keyword(s):  
Density Functional ◽  
Magnetic Moments ◽  
Stable Configuration ◽  
Many Body ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Au Clusters ◽  
The Density Functional Theory ◽  
Ground State Structures ◽  
Body Potential

The ground state structures of Co 12 X ( X = Ni , Ag , Pt , Au ) clusters are obtained by a genetic algorithm with a Gupta-like many-body potential, and further optimized using the density functional theory with generalized gradient approximation. The structures of Co 12 X have a slightly distorted icosahedral pattern. The X atom is on the surface for the most stable configuration. Their total magnetic moments are 0μ B , 3μ B , 21μ B , and 22μ B , respectively. The reasons for the reduction of magnetism of Co 12 X are discussed in detail.

First principle calculations of hydrogen sulfide adsorption and dissociation on pure Pd (111) and Au (111), and alloy Pd/Au (111) and Au/Pd (111) surfaces

2014 ◽  
Vol 13 (08) ◽  
pp. 1450065 ◽  
Author(s):  
Na Liu ◽  
Xue-Ye Wang ◽  
Ya-Li Wan
Keyword(s):  
Hydrogen Sulfide ◽  
Metal Surfaces ◽  
Density Functional ◽  
Generalized Gradient ◽  
Dissociation Process ◽  
Functional Theory ◽  
Band Center ◽  
Plane Wave Method ◽  
Adsorption Energies ◽  
Adsorption And Dissociation

The hydrogen sulfide adsorption and dissociation on pure Pd (111) and Au (111), alloy Pd / Au (111) and Au / Pd (111) surfaces have been investigated using the pseudo-potential plane wave method within the generalized-gradient approximation density functional theory (GGA+DFT). The results show that H 2 S tends to be adsorbed on top site, HS prefers to locate on bridge site, and the S and H locate on fcc site on various surfaces. Compared the adsorption of sulfur-containing species and hydrogen on pure and alloy metal surfaces, a similar trend of adsorption energies on the metal surfaces ( Pd / Au (111) > Pd (111) > Au (111) > Au / Pd (111)) is found. In addition, the dissociation process on the Pd (111) and Pd / Au (111) surfaces is predicted to be exothermic. However, on Au (111) and Au / Pd (111), the dissociation process is endothermic. The work reveals that H 2 S dissociation is more likely to happen on Pd / Au (111) surface. Finally, the adsorption energies of adsorbate on metal surfaces have strong correlation with the d-band center. The d-band center moves away from the Fermi level, and the adsorption energy decreases. According to the LDOS analysis, the inner Au atoms of Pd / Au (111) can enhance the top-layer d-band intensity, whereas the inner Pd atoms of Au / Pd (111) cause the opposite effect. The further electronic state analysis reveals the interaction between H 2 S and metal surfaces.

Structures and stabilities of (OsnN)0,±(n = 7 − 11) clusters

2015 ◽  
Vol 29 (23) ◽  
pp. 1550163
Author(s):  
W. L. Guo ◽  
L. L. Zhang ◽  
M. Luo ◽  
X. R. Zhang
Keyword(s):  
Density Functional Theory ◽  
Ionization Potential ◽  
Electron Affinity ◽  
Ground State ◽  
Density Functional ◽  
Magic Number ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
Ground State Structures

Structures and stabilities of [Formula: see text] clusters have been systematically studied via using density functional theory (DFT) with generalized gradient approximation (GGA). The calculations show that the stable configurations of [Formula: see text] are such structures with one N atom bonded to the external of the basic constructions consisting of Os atoms. Meanwhile, [Formula: see text] clusters [Formula: see text] represent “magic number” effect, and 8 is the magic number. Additionally, the ground-state structures of [Formula: see text] clusters have the best stability, while that of [Formula: see text] cluster possesses the worst stability. The result of the study on the ionization potential (IP) and the electron affinity (EA) shows that there are not topological differences among the configurations of [Formula: see text][Formula: see text] clusters.

Electron correlation effects in small iron clusters

2004 ◽  
Vol 1 (4) ◽  
pp. 288-296 ◽  
Author(s):  
G. Rollmann ◽  
P. Entel
Keyword(s):  
Electron Correlation ◽  
Density Functional ◽  
Magnetic Moments ◽  
Coulomb Repulsion ◽  
Correlation Effects ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Jahn Teller ◽  
Electron Correlation Effects ◽  
Ground State Structures

We present results of first-principles calculations of structural, magnetic, and electronic properties of small Fe clusters. It is shown that, while the lowest-energy isomers of Fe3 and Fe4 obtained in the framework of density functional theory within the generalized gradient approximation (GGA) are characterized by Jahn-Teller-like distortions away from the most regular shapes (which is in agreement with other works), these distortions are reduced when electron correlation effects are considered explicitly as within the GGA+U approach. At the same time, the magnetic moments of the clusters are enhanced with respect to the pure GGA case, resulting in maximal moments (in the sense of Hund’s rules) of 4 μB per atom for the ground state structures of Fe3 and Fe4, and a total moment of 18 μB for Fe5. This already happens for moderate values of the Coulomb repulsion parameter U̴ 2.0 eV and is explained by changes in the electronic structures of the clusters.

scholarly journals Study of Structural and Electronic Behavior of BeH2 as Hydrogen Storage Compound: An Ab Initio Approach

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Vikas Nayak ◽  
Suman Banger ◽  
U. P. Verma
Keyword(s):  
Hydrogen Storage ◽  
Electronic Properties ◽  
Density Functional ◽  
Correlation Energy ◽  
Electronic Band Structure ◽  
Unit Cell ◽  
Generalized Gradient ◽  
Hydrogen Atoms ◽  
Electronic Band ◽  
Cell Parameters

The quantum mechanical calculations based on density functional theory (DFT) have been performed to study ground state structural and electronic properties of BeH2 and along with doping of two (BeH2 + 2H) and four (BeH2 + 4H) hydrogen atoms. The generalized gradient approximation (GGA) has been employed for the exchange correlation energy. The most stable space group of BeH2 is Ibam. Its optimized equilibrium unit cell volume, bulk modulus and its first-order pressure derivative, and electronic properties have been obtained. Our predicted unit cell parameters for BeH2  a=9.2463 Å, b=4.2352 Å, and c=7.8464 Å are in very good agreement with the earlier reported experimental and theoretical results. The electronic band structure of BeH2 shows its behavior as an insulator. The stability of BeH2 along with doped hydrogen atoms increases, while the energy band gap decreases with the increase in number of doped hydrogen atoms. On these bases, we predict that BeH2 is a promising material for hydrogen storage.

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