scholarly journals Density-Functional-Theory Calculations of Formation Energy of the Nitrogen-Doped Diamond

2018 ◽  
Vol 18 (4) ◽  
pp. 749 ◽  
Author(s):  
Sholihun Sholihun ◽  
Hana Pratiwi Kadarisman ◽  
Pekik Nurwantoro
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Formation Energy ◽  
Geometry Optimization ◽  
Density Functional Theory Calculations ◽  
Energy Difference ◽  
Stable Configuration ◽  
Functional Theory ◽  
Substitutional Site ◽  
Nitrogen Doped

The geometry optimization of the nitrogen-doped diamond has been carried out by the density functional theory (DFT) calculations. We model the defective diamond of substitutional and interstitial nitrogen atoms by using a simple-cubic supercell. Atoms in the supercell are relaxed by allowing them to move so that the atomic forces are less than 5.0 × 10-3 eV/Å. We calculate the formation energy for substitutional and interstitial sites. We find that the formation energy for the substitutional defect is10.89 eV. We check the convergence of the calculation with respect to the k×k×k - Monkhorst-Pack grids. We show that the energy difference between k = 4 and 6 is very small (7.0 meV). We also check the calculations by using a 216-sites supercell and find that the energy difference is 0.10 eV. Thus, the calculations of the formation energy converge well. As for the interstitial defect, we model some possible configurations and find that the smallest formation energy is 21.88 eV. Therefore, the most stable configuration of the nitrogen-doped diamond belongs to the substitutional site.

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.

A density functional theory study on the structural and electronic properties of PbxSbySez (x + y + z = 2, 3) clusters

2018 ◽  
Vol 32 (03) ◽  
pp. 1850024
Author(s):  
Rengi̇n Peköz ◽  
Şaki̇r Erkoç
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Ground States ◽  
Density Functional Theory Calculations ◽  
Energy Difference ◽  
Binding Energies ◽  
Functional Theory ◽  
Structural And Electronic Properties ◽  
Scalene Triangle

The structural and electronic properties of neutral ternary PbxSbySez clusters (x + y + z = 2, 3) in their ground states have been explored by means of density functional theory calculations. The geometric structures and binding energies are systematically explored and for the most stable configurations of each cluster type vibrational frequencies, charges on atoms, energy difference between highest occupied and lowest unoccupied molecular orbitals, and the possible dissociations channels have been analyzed. Depending on being binary or ternary cluster and composition, the most energetic structures have singlet, doublet or triplet ground states, and trimers prefer to form isosceles, equilateral or scalene triangle structure.

Density Functional Calculations on the Metal-Polymer Interfaces

1993 ◽  
Vol 304 ◽  
Author(s):  
A. Selmani ◽  
A. Ouhlal ◽  
A. Yelon
Keyword(s):  
Density Functional ◽  
Vibrational Analysis ◽  
Density Functional Theory Calculations ◽  
Energy Difference ◽  
Stable Configuration ◽  
Polymer Interfaces ◽  
Functional Theory ◽  
Model Molecule ◽  
Spin Polarisation ◽  
Metal Polymer

AbstractBonding of chromium to the polyimide, PMDA-ODA, surface is still subject to debate. In an attempt to clarify this problem, we have performed density functional theory calculations on a model molecule, phthalimide, which contains the most reactive functionalities of the polyimide PMDA part. Considering only the low spin case, we find that chromium bonds preferentially to the phenyl ring. However, when we release the spin polarisation and optimise the structure, we find that the absolute stable configuration is that of chromium in a quintet state at a carbonyl group. The energy difference is 0.30 eV. The complete optimised structures are determined. The infrared spectrum have been calculated for phthalimide and compared to experimental spectra. The agreement is excellent. A vibrational analysis for the Cr/phthalimide system, in both configurations (Cr on C=O and Cr on phenyl), in their stable spin states, is presented.

scholarly journals Band gap narrowing in nitrogen-doped La2Ti2O7 predicted by density-functional theory calculations

2015 ◽  
Vol 17 (14) ◽  
pp. 8994-9000 ◽  
Author(s):  
Junying Zhang ◽  
Wenqiang Dang ◽  
Zhimin Ao ◽  
Scott K. Cushing ◽  
Nianqiang Wu
Keyword(s):  
Density Functional Theory ◽  
Photocatalytic Activity ◽  
Band Gap ◽  
Density Functional ◽  
Energy State ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Nitrogen Doped ◽  
Band Gap Narrowing ◽  
Visible Light Photocatalytic

NS co-existing with VO in La2Ti2O7 narrows the band gap and removes the localized energy state, leading to a strong visible light photocatalytic activity and enhancement of the UV performance.

Density-functional theory calculations, luminescence properties and fluorescence ratiometric thermo-sensitivity for a novel borate based red phosphor: NaBaSc(BO3)2:Ce3+,Mn2+

2019 ◽  
Vol 7 (7) ◽  
pp. 1982-1990 ◽  
Author(s):  
Wanying Geng ◽  
Xufeng Zhou ◽  
Jianyan Ding ◽  
Yuhua Wang
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Formation Energy ◽  
Density Functional Theory Calculations ◽  
Luminescence Properties ◽  
Functional Theory ◽  
Red Phosphor ◽  
Red Emitting Phosphor ◽  
Thermo Sensitivity

Formation energy, electronic structure and fluorescence ratiometric thermo-sensitive study of a novel red emitting phosphor NaBaSc(BO3)2:Ce3+,Mn2+.

Density functional theory calculations for the band gap and formation energy of Pr4−xCaxSi12O3+xN18−x; a highly disordered compound with low symmetry and a large cell size

2017 ◽  
Vol 19 (25) ◽  
pp. 16702-16712 ◽  
Author(s):  
Sung Un Hong ◽  
Satendra Pal Singh ◽  
Myoungho Pyo ◽  
Woon Bae Park ◽  
Kee-Sun Sohn
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Band Gap ◽  
Cell Size ◽  
Density Functional ◽  
Formation Energy ◽  
Density Functional Theory Calculations ◽  
Large Cell ◽  
Functional Theory ◽  
Low Symmetry

A pragmatic strategy adopted to find a suitable configuration for DFT calculations of a disordered compound, Pr4−xCaxSi12O3+xN18−x, to obtain an acceptable band gap.

Superionic and electronic conductivity in monolayer W2C: ab initio predictions

2017 ◽  
Vol 5 (22) ◽  
pp. 11094-11099 ◽  
Author(s):  
Abdus Samad ◽  
Aamir Shafique ◽  
Hye Jung Kim ◽  
Young-Han Shin
Keyword(s):  
Density Functional Theory ◽  
Ab Initio ◽  
Density Functional ◽  
Formation Energy ◽  
Electronic Conductivity ◽  
Density Functional Theory Calculations ◽  
Functional Theory

Using density functional theory calculations, a freestanding monolayer of W2C in the 2H phase is explored to find its stability in terms of formation energy and phonon vibrations and the diffusion of Li/Na from an H-site to a nearby H-site through three different paths.

scholarly journals Density functional theory calculations of merohedric twinning in KLiSO4

2019 ◽  
Vol 234 (4) ◽  
pp. 211-217
Author(s):  
Hans Grimmer ◽  
Bernard Delley
Keyword(s):  
Density Functional Theory ◽  
Aqueous Solutions ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Energy Difference ◽  
Boundary Plane ◽  
Temperature Phase ◽  
Functional Theory ◽  
Transformation Twins ◽  
Polysynthetic Twin

Abstract Density functional theory (DFT) calculations have been performed on five models of periodic, polysynthetic twin interfaces in the ambient-temperature phase of KLiSO4, which has space group P63. The models represent the three merohedric twin laws (m||z, 2⊥z and 1̅) with boundary plane (1 0 1̅ 0), also with boundary plane (0 0 0 1) in case of m, and with boundary plane (1 2̅ 1 0) in case of 1̅. The models satisfy stoichiometry at the boundary plane and maintain the fourfold coordination of the Li and S atoms and the twofold coordination of the oxygen atoms. Relaxed lattice parameters and atomic positions were determined by DFT, using the DMol3 code with functional PBEsol. The energy difference between polysynthetic twin and single crystal per primitive cell of the twin is 0.0009 eV for m(0 0 0 1), 0.09 eV for 1̅(1 0 1̅ 0), 0.58 eV for m(1 0 1̅ 0) and 0.55 eV for 2(1 0 1̅ 0). In KLiSO4 crystals grown from aqueous solutions the first twin was frequently observed, similarly also the second twin in Cr-doped crystals, whereas the third twin appeared only rarely and the fourth was not observed. Not only for KLiSO4 but also for quartz, the energy of twins and the frequency of their occurrence are closely connected for crystals grown from aqueous solutions, whereas for the formation of transformation twins the availability of twin nuclei plays a major role.

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