Understanding the Formation Energy of Transition Metal Hydrides

2002 ◽  
Vol 730 ◽  
Author(s):  
Huw J. Smithson ◽  
Dane Morgan ◽  
Anton Van der Ven ◽  
Chris Marianetti ◽  
Ashley Pedith ◽  
...  
Keyword(s):  
Transition Metal ◽  
Density Functional ◽  
Formation Energy ◽  
Metal Hydrides ◽  
Functional Theory ◽  
Hydride Formation ◽  
Transition Metal Hydrides ◽  
Inverse Stability ◽  
Host Metal ◽  
The Stability

AbstractA detailed analysis of the formation energies of transition metal hydrides is presented. The hydriding energies are computed for various crystal structures using Density Functional Theory. The process of hydride formation is broken down into three consecutive, hypothetical reactions in order to analyse the different energy contributions, and explain the observed trends. We find that the stability of the host metal is very significant in determining the formation energy, thereby providing a more fundamental justification for Miedema's “law of inverse stability” [1] (the more stable the metal, the less stable the hydride). The conversion of the host metal to the structure formed by the metal ions in the hydride (fcc in most cases) is only significant for metals with a strong bcc preference such as V and Cr - this lowers the driving force for hydride formation. The final contribution is the chemical bonding between the hydrogen and the metal. This is the only contribution that is negative, and hence favourable to hydride formation. We find that it is dominated by the position of the Fermi level in the host metal.

Density functional theory study of transition metals doped B80 fullerene

2014 ◽  
Vol 13 (06) ◽  
pp. 1450050 ◽  
Author(s):  
Jianguang Wang ◽  
Li Ma ◽  
Yanhua Liang ◽  
Meiling Gao ◽  
Guanghou Wang
Keyword(s):  
Density Functional Theory ◽  
Outer Surface ◽  
Density Functional ◽  
Formation Energy ◽  
Magnetic Moments ◽  
Density Functional Theory Calculations ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Energy Gaps ◽  
The Stability

Density functional theory calculations have been carried out to investigate 3d, Pd and Pt transition metal (TM) atoms exohedrally and endohedrally doped B 80 fullerene. We find that the most preferred doping site of the TM atom gradually moves from the outer surface ( TM = Sc ), to the inner surface ( TM = Ti and V ) and the center ( TM = Cr , Mn , Fe and Zn ), then to the outer surface ( TM = Co , Ni , Cu , Pd , and Pt ) again with the TM atom varying from Sc to Pt . From the formation energy calculations, we find that doping TM atom can further improve the stability of B 80 fullerene. The magnetic moments of doped V , Cr , Mn , Fe , Co and Ni atoms are reduced from their free-atom values and other TM atoms are completely quenched. Charge transfer and hybridization between 4s and 3d states of TM and 2s and 2p states of B were observed. The energy gaps of TM @ B 80 are usually smaller than that of the pure B 80. Endohedrally doped B 80 fullerene with two Mn and two Fe atoms were also considered, respectively. It is found that the antiferromagnetic (AFM) state is more energetically favorable than the ferromagnetic (FM) state for Mn 2- and Fe 2@ B 80. The Mn and Fe atoms carry the residual magnetic moments of ~ 3 μB and 2 μB in the AFM states.

scholarly journals Effect of Doping Concentration on Structural Stability and Formation Energy of the Fluorine Doped Hexagonal Molybdenum Dioxide (MoO2). A First Principle Study.

2021 ◽  
pp. 55-59
Author(s):  
Yakubu Tanko ◽  
Alhassan Shuaibu ◽  
Aminu Abdulrahman ◽  
Oyedare Olusola ◽  
Mustapha Isa ◽  
...  
Keyword(s):  
Bond Length ◽  
Density Functional ◽  
Formation Energy ◽  
Doping Concentration ◽  
Generalized Gradient ◽  
Molybdenum Dioxide ◽  
Functional Theory ◽  
Free Atoms ◽  
The Stability ◽  
Quantum Espresso

The structural properties of undoped and Fluorine doped Hexagonal Molybdenum dioxide (MoO2) with different doping concentrations have been calculated using Density Functional Theory (DFT) within Generalized Gradient Approximation (GGA) as implemented in Quantum Espresso (QE). The calculated results were for the formation energy of 4.17%, 8.33%, 12.5%, of F doped MoO2 are 232.5eV, 463.0eV, and 698.5eV respectively, which show the variation of energy based on the increase in the doping concentration that led to having the breakage of bond in the structure of the compound. The undoped and 4.17% of F doped MoO2 have three free atoms, which maintain the stability of the structure, but when the doping concentration was increased, the bond breaks simultaneously which led to having four and five free atoms for 8.33%, and 12.5% of F doped MoO2 respectively. This makes 4.17% of F doped MoO2 with 17.09Ry more stable. Similarly, the bond length of undoped MoO2 was 2.2505pm, but when doped with 4.17% of F it changes to 2.3030pm which indicates a greater stability of the structure concentrations of the dopant above 4.17% reduced the bond length, which made the structure less stable.

scholarly journals Ultra-strong stability of double-sided fluorinated monolayer graphene and its electrical property characterization

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Haidong Wang ◽  
Masahiro Narasaki ◽  
Zhongwei Zhang ◽  
Koji Takahashi ◽  
Jie Chen ◽  
...  
Keyword(s):  
Density Functional ◽  
Formation Energy ◽  
Density Functional Theory Calculations ◽  
Strong Stability ◽  
Monolayer Graphene ◽  
Efficient Design ◽  
Functional Theory ◽  
Fluorinated Graphene ◽  
The Stability ◽  
Property Characterization

Abstract Fluorinated graphene has a tunable band gap that is useful in making flexible graphene electronics. But the carbon–fluorine (C–F) bonds in fluorinated graphene can be easily broken by increased temperature or electron beam irradiation. Here, we demonstrate that the stability of fluorinated graphene is mainly determined by its C–F configuration. The double-sided fluorinated graphene has a much stronger stability than the single-sided fluorinated graphene under the same irradiation dose. Density functional theory calculations show that the configuration of double-sided fluorinated graphene has a negative and low formation energy, indicating to be an energetically stable structure. On the contrary, the formation energy of single-sided fluorinated graphene is positive, leading to an unstable C–F bonding that is easily broken by the irradiation. Our findings make a new step towards a more stable and efficient design of graphene electronic devices.

scholarly journals Stacking stability and sliding mechanism in weakly bonded 2D transition metal carbides by van der Waals force

RSC Advances ◽  
2017 ◽  
Vol 7 (88) ◽  
pp. 55912-55919 ◽  
Author(s):  
H. Zhang ◽  
Z. H. Fu ◽  
D. Legut ◽  
T. C. Germann ◽  
R. F. Zhang
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Density Functional ◽  
Van Der Waals ◽  
Two Dimensional ◽  
Metal Carbides ◽  
Functional Theory ◽  
Transition Metal Carbides ◽  
Sliding Mechanism ◽  
The Stability

The stability of the stacked two-dimensional (2D) transition metal carbides and their interlayered friction in different configurations are comparatively studied by means of density functional theory (DFT).

scholarly journals Theoretical Description of the Physical/chemical Contributions Determining the Stability of Transition-Metal Doped Phosphorene Nanosheets

2020 ◽  
Author(s):  
Sasha Gazzari ◽  
Kerry Wrighton-Araneda ◽  
Diego Cortes-Arriagada
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Transition Metals ◽  
Density Functional ◽  
Theoretical Description ◽  
Energy Decomposition ◽  
Functional Theory ◽  
Physical Chemical ◽  
The Stability ◽  
Metal Doped

In this report, we explore the stability of doped-phosphorene nanosheets with first-row transition metals in the framework of density functional theory and by using a bonding characterization and energy decomposition analyses.

scholarly journals Theoretical Description of the Physical/chemical Contributions Determining the Stability of Transition-Metal Doped Phosphorene Nanosheets

2020 ◽  
Author(s):  
Sasha Gazzari ◽  
Kerry Wrighton-Araneda ◽  
Diego Cortes-Arriagada
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Transition Metals ◽  
Density Functional ◽  
Theoretical Description ◽  
Energy Decomposition ◽  
Functional Theory ◽  
Physical Chemical ◽  
The Stability ◽  
Metal Doped

In this report, we explore the stability of doped-phosphorene nanosheets with first-row transition metals in the framework of density functional theory and by using a bonding characterization and energy decomposition analyses.

Evaluating Transition Metal Barrier Heights with the Latest DFT Exchange–Correlation Functionals – the MOBH35 Benchmark Dataset

2019 ◽  
Author(s):  
Mark Iron ◽  
Trevor Janes
Keyword(s):  
Transition Metal ◽  
Density Functional ◽  
Computational Cost ◽  
Basis Set ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Barrier Heights ◽  
Complete Basis Set ◽  
Complete Basis Set Limit ◽  
Hybrid Functionals

A new database of transition metal reaction barrier heights – MOBH35 – is presented. Benchmark energies (forward and reverse barriers and reaction energy) are calculated using DLPNO-CCSD(T) extrapolated to the complete basis set limit using a Weizmann1-like scheme. Using these benchmark energies, the performance of a wide selection of density functional theory (DFT) exchange–correlation functionals, including the latest from the Truhlar and Head-Gordon groups, is evaluated. It was found, using the def2-TZVPP basis set, that the ωB97M-V (MAD 1.8 kcal/mol), ωB97X-V (MAD 2.1 kcal/mol) and SCAN0 (MAD 2.1 kcal/mol) hybrid functionals are recommended. The double-hybrid functionals PWPB95 (MAD 1.6 kcal/mol) and B2K-PLYP (MAD 1.8 kcal/mol) did perform slightly better but this has to be balanced by their increased computational cost.

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