scholarly journals Systematic Approach To Calculate the Band Gap Energy of a Disordered Compound with a Low Symmetry and Large Cell Size via Density Functional Theory

ACS Omega ◽  
2016 ◽  
Vol 1 (3) ◽  
pp. 483-490 ◽  
Author(s):  
Woon Bae Park ◽  
Sung Un Hong ◽  
Satendra Pal Singh ◽  
Myoungho Pyo ◽  
Kee-Sun Sohn
Keyword(s):  
Density Functional Theory ◽  
Band Gap ◽  
Cell Size ◽  
Density Functional ◽  
Systematic Approach ◽  
Large Cell ◽  
Band Gap Energy ◽  
Functional Theory ◽  
Gap Energy ◽  
Low Symmetry

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.

scholarly journals Electronic properties of palladium diselenide by density functional theory

2017 ◽  
Vol 13 (3) ◽  
Author(s):  
Ying Xuan Ng ◽  
Rashid Ahmed ◽  
Abdullahi Lawal ◽  
Bakhtiar Ul Haq ◽  
Afiq Radzwan ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Band Gap ◽  
Electronic Properties ◽  
Density Functional ◽  
Band Gap Energy ◽  
Partial Density ◽  
Full Potential ◽  
Functional Theory ◽  
Lattice Constants ◽  
Gap Energy

The knowledge of the structural and electronic properties of a material is important in various applications such as optoelectronics and thermoelectric devices. In this study, we are using full potential linearized augmented plane wave method framed within density functional theory provided by WIEN2k to optimize the structure of PdSe2 in orthorhombic (Pbca) phase and calculate its electronic properties. With the implementation of local density approximation (LDA), Perdew-Burke-Ernzerhof parameterization of generalized gradient approximation (PBE-GGA), Wu-Cohen parameterization of GGA (WC-GGA), and PBE correction for solid GGA (PBEsol-GGA), the computed results of lattice constants are found to be within 5% error with the experiment data. Also, our calculated indirect band gap energy was found to be ~0.24 eV by LDA along with modified Becke-Johnson potential functional (mBJ) with experimental lattice constants and ~0.52 eV by using PBE-GGA with optimized lattice constants. However, the effect of spin-orbit coupling is not found too much on the band gap energy. By analyzing the partial density of states, we identify that d-orbital of Pd is demonstrating a slightly more significant contribution to both the valence and conduction band near to Fermi level which is also in agreement with the previous first principles study.

scholarly journals On the molecular modeling analyses of sodium carboxymethyl cellulose treated with acetic acid

2019 ◽  
Vol 8 (2) ◽  
pp. 553-557 ◽  
Keyword(s):  
Acetic Acid ◽  
Band Gap ◽  
Carboxymethyl Cellulose ◽  
Density Functional ◽  
Band Gap Energy ◽  
Sodium Carboxymethyl Cellulose ◽  
Functional Theory ◽  
Gap Energy ◽  
Model Molecule ◽  
Homo Lumo

Model molecules for sodium carboxymethyl cellulose (Na-CMC) (monomer), glycerol, acetic acid and Na-CMC-glycerol-acetic acid are optimized with Density Functional Theory (DFT) at B3LYP/3-21G*. For the optimized models, total dipole moment (TDM), the highest occupied and lowest unoccupied molecular orbitals (HOMO/LUMO band gap energy), and molecular electrostatic potentials (ESP) are calculated at the same method to give an explanation for the possibility of using Na-CMC-Glycerol-acetic acid model molecule in electrochemical devices, gas sensors and batteries. As a result of the substitution of Na-CMC with glycerol, TDM increased from 7.7141 Debye to 22.4942 Debye which is approximately equal to three times that of Na-CMC. However, HOMO/LUMO band gap energy decreased from 0.9040 eV to 0.5072 eV. After the addition of acetic acid to Na-CMC-glycerol model, TDM increased to24.7270 Debye and HOMO/LUMO band gap energy decreased to 0.4939 eV. Both TDM and HOMO/LUMO band gap energy values are improved by increasing the acetic acid units, where TDM became 25.3510 Debye and HOMO/LUMO band gap energy decreased to 0.3815 eV. The results of ESP indicated that the addition of glycerol and acetic acid to Na-CMC increased the electronegativity of Na-CMC which in turn enhanced its electronic properties.

Density functional theory study on the adsorption of valproic acid to doped fullerenes

2018 ◽  
Vol 41 (3-4) ◽  
pp. 67-71 ◽  
Author(s):  
Özgür Alver ◽  
Cemal Parlak ◽  
Mustafa Şenyel ◽  
Ponnadurai Ramasami
Keyword(s):  
Drug Delivery ◽  
Density Functional Theory ◽  
Valproic Acid ◽  
Density Functional ◽  
Band Gap Energy ◽  
Sensor Technology ◽  
Functional Theory ◽  
Gap Energy ◽  
Interaction Sites ◽  
Doped Fullerenes

Abstract Fullerenes and heteroatom doped fullerenes exhibit high potential as drug delivery agents in sensor technology and medical applications. We investigated, using density functional theory, the possible interaction sites and the nature of interaction, adsorption energy assessments, band gap energy evaluations, charge transfer analyses, and some diagnostic vibrational band assignments for valproic acid (VPA) and aluminum, silicon, and boron decorated fullerene systems. The present research shows that VPA has strong interaction with the doped fullerene cages particularly at its carbonyl edge. Therefore, these doped fullerenes can be suggested as possible drug delivery agents.

Density Functional Theory (DFT) Study: Electronic Properties of Silicene under Uniaxial Strain as H2S Gas Sensor

2016 ◽  
Vol 675-676 ◽  
pp. 15-18 ◽  
Author(s):  
Sasfan Arman Wella ◽  
Irfan Dwi Aditya ◽  
Triati Dewi Kencana Wungu ◽  
Suprijadi
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Density Functional ◽  
Band Gap Energy ◽  
Engineering Strain ◽  
Functional Theory ◽  
First Principle Calculation ◽  
Gap Energy ◽  
Center Configuration ◽  
Structural And Electronic Properties

First principle calculation is performed to investigate structural and electronic properties of strained silicene (silicon analogue of graphene) when absorbing the hydrogen sulfide molecule gas. Two configuration of silicene-H2S system, center and hollow configuration, is checked under 0% (pure), 5%, and 10% uniaxial engineering strain. We report that the silicene-H2S system in center configuration has larger binding energy compare to the silicene-H2S system in hollow configuration. The results show that H2S is physisorbed on silicene. In this work, we also find the change of band gap energy (~60 meV) is appearing when H2S interacted with silicene in center configuration, whereas the band gap energy of silicene has no change when interacted with H2S in hollow configuration.

On the Spectroscopic Analyses of Polytetrafluoroethylene Coated with Nano ZnO and SiO2

2022 ◽  
Author(s):  
Maroof A. Hegazy ◽  
Rasha Ghoneim ◽  
Hend A. Ezzat ◽  
Heba Y. Zahran ◽  
Ibrahim S. Yahia ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Band Gap ◽  
Density Functional ◽  
Quantitative Structure Activity Relationship ◽  
Band Gap Energy ◽  
Layer By Layer ◽  
Functional Theory ◽  
Gap Energy ◽  
Model Structures ◽  
Homo Lumo

Abstract On polytetrafluoroethylene (PTFE) polymer nanocomposites coated with basically two metal oxides (MOs), SiO2 and ZnO, as well as a mixture of the two MOs, density functional theory (DFT) computations were performed. The B3LYPL/LAN2DZ model was used to evaluate PTFE polymer nano composites suggested model structures. The physical and electrical properties of PTFE modified on surface with ZnO and SiO2 coated layer by layer change Total dipole moment (TDM) and HOMO/LUMO band gap energy ∆Eto be 13.0082 Debye and 0.6889 eV, respectively. Moreover, TDM and band gap energy (∆E) improved to 10.6053 Debye and 0.2727 eV, respectively, when the nanofiller was increased to 8 atoms. In addition, the results of the Molecular Electrostatic Potential (MESP) and the Quantitative Structure Activity Relationship (QSAR) showed that PTFE coated with ZnO and SiO2 improved electrical characteristics and thermal stability. As PTFE coated with ZnO and SiO2 layer by layer, all stability characteristics, including electrical and thermal stability, were enhanced. The improved PTFE can be used as a corrosion-inhibiting layer for astronaut suits, according to the predicted results.

Phase Transition and Electronic Properties of LiBH4 via First-Principles Calculations

2014 ◽  
Vol 971-973 ◽  
pp. 119-122
Author(s):  
Hai Ping Wang
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Density Functional ◽  
Density Functional Theory Method ◽  
Band Gap Energy ◽  
First Principles Calculations ◽  
Volume Data ◽  
Functional Theory ◽  
Gap Energy ◽  
Phase Sequence

The transition phase and electronic properties of LiBH4 were investigated by ab initio plane-wave pseudopotential density functional theory method. According to the theoretical calculation, the phase sequence Pnma → P21/c → Cc is obtained. The phase transitions Pnma → P21/c and P21/c → Cc are at the pressure of 1.64 GPa and 2.83 GPa, respectively, by total energy-volume data. As the pressure increases, the value of the band gap energy is reduced from 7.1 (Pnma) to 6.1 eV (Cc). Moreover, the electronic properties of the high pressure phases are discussed. The electronic properties are linked to the band gap energy, total (partly) density of states and atoms (bond) populations.

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