scholarly journals A NOVEL FRACTAL GEOMETRY DOPING FOR GRAPHENE NANORIBBON AND THE OPTIMIZATION OF CRYSTAL: A DENSITY FUNCTIONAL THEORY (DFT) STUDY

2020 ◽  
Vol 17 (35) ◽  
pp. 1148-1158
Author(s):  
Mohammed L. JABBAR ◽  
Kadhum J. AL-SHEJAIRY
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Energy Gap ◽  
Minimum Energy ◽  
Graphene Nanoribbon ◽  
Chemical Doping ◽  
Functional Theory ◽  
Lower Reactivity ◽  
The Density Functional Theory ◽  
Semiconductor Behavior

Chemical doping is a promising route to engineering and controlling the electronic properties of the zigzag graphene nanoribbon (ZGNR). By using the first-principles of the density functional theory (DFT) calculations at the B3LYP/ 6-31G, which implemented in the Gaussian 09 software, various properties, such as the geometrical structure, DOS, HOMO, LUMO infrared spectra, and energy gap of the ZGNR, were investigated with various sites and concentrations of the phosphorus (P). It was observed that the ZGNR could be converted from linear to fractal dimension by using phosphorus (P) impurities. Also, the fractal binary tree of the ZGNR and P-ZGNR structures is a highlight. The results demonstrated that the energy gap has different values, which located at this range from 0.51eV to 1.158 eV for pristine ZGNR and P-ZGNR structures. This range of energy gap is variable according to the use of GNRs in any apparatus. Then, the P-ZGNR has semiconductor behavior. Moreover, there are no imaginary wavenumbers on the evaluated vibrational spectrum confirms that the model corresponds to minimum energy. Then, these results make P-ZGNR can be utilized in various applications due to this structure became more stable and lower reactivity.

scholarly journals Chloroquine drug and Graphene complex for treatment of COVID-19

2020 ◽  
Author(s):  
Saeedeh Mohammadi ◽  
Mohammad Esmailpour ◽  
Mina Mohammadi
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Energy Gap ◽  
Dft Method ◽  
Complex State ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Structural And Electrical Properties ◽  
Suitable Structure ◽  
Drug Complex

Abstract This paper is a new step in helping the treatment of coronavirus by improving the performance of chloroquine drug. For this purpose, we propose a complex of chloroquine drug with graphene nanoribbon (GNR) scheme. We compute the structural and electrical properties and absorption of chloroquine (C18H26ClN3) and GNR complex using the density functional theory (DFT) method. By creating a drug and GNR complex, the density of states of electrons increases and the energy gap decreases compared to the chloroquine. Also, using absorption calculations and spectrums such as infrared and UV-Vis spectra, we showed that GNR is a suitable structure for creating chloroquine drug complex. Our results show that the dipole moment, global softness and electrophilicity for the drug complex increases compared to the non-complex state. Our calculations can be useful for increasing performance and reducing the side effects of chloroquine, and thus can be effective in treating coronavirus.

Studying of B, N, S, Si and P Doped (5, 5) Carbon Nanotubes by the Density Functional Theory

2012 ◽  
Vol 463-464 ◽  
pp. 1488-1492 ◽  
Author(s):  
Yan Li Wang ◽  
Ke He Su ◽  
Jun Ping Zhang
Keyword(s):  
Carbon Nanotubes ◽  
Density Functional Theory ◽  
Density Functional ◽  
Periodic Boundary ◽  
Energy Gap ◽  
Periodic Boundary Conditions ◽  
Functional Theory ◽  
Energy Gaps ◽  
The Density Functional Theory ◽  
Metal Conductivity

The B, N, S, Si and P atoms doped single walled (5, 5) carbon nanotubes were studied by density functional theory B3LYP/3-21G (d) with the periodic boundary conditions. The ultra long tube models were calculated and the structures, energies and the band structures were obtained. The N, Si and S doped nanotubes have narrow energy gap with metal conductivity whereas B and P doped nanotubes have overlapped energy gaps with or semi-metal conductivity.

A Density Functional Theory Study on the Structures and Electronic Properties of XAln (X = Br, I; n = 3–15) Clusters

2019 ◽  
Vol 74 (2) ◽  
pp. 121-129 ◽  
Author(s):  
Ming Hui ◽  
Qing-Huai Zhao ◽  
Zhi-Peng Wang ◽  
Shuai Zhang ◽  
Gen-Quan Li
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Three Dimensional ◽  
Density Functional Theory Calculations ◽  
Chemical Hardness ◽  
Geometrical Structures ◽  
Functional Theory ◽  
The Density Functional Theory

AbstractThe effects of halogen element X (X = Br, I) doping on the geometrical structures and electronic properties of neutral aluminium clusters are systematically studied by utilising the density functional theory calculations. The structures of X-doped clusters show the three-dimensional forms with increasing atomic number except for n = 3 and X (X = Br, I) atom prefer to occupy the surface site of the host Aln clusters. BrAl7 and IAl7 clusters are the most stable geometries. The HOMO-LUMO energy gap and chemical hardness show an odd–even alternative phenomenon. The charges always transfer from the Al atoms to the X (X = Br, I) atom. Finally, the dipole and polarisability are discussed.

scholarly journals Thyroxine: A Theoretical Study of the Vibrational and Electronic Properties

2020 ◽  
Vol 3 (1) ◽  
pp. 31-40
Author(s):  
Ricardo V. K. Rizzon ◽  
Zélia M. da Costa Ludwig ◽  
Ricardo V. K. Rizzon ◽  
Lucas Modesto da Costa ◽  
Valdemir Ludwig
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Theoretical Study ◽  
Minimum Energy ◽  
Functional Theory ◽  
Structures And Properties ◽  
The Density Functional Theory ◽  
Infra Red ◽  
Simulation Results

Through this work, we systematically studied the structural, vibrational and electronic properties of the fundamental state of the isolated thyroxine(3,5,3’,5-tetraiodothyronine). The minimum energy structures and properties were obtained using the Density Functional Theory (DFT). Our simulation results were compared with experimental results, including infra-red and Raman spectroscopy with an emphasis on the properties of iodine atoms. The UV-vis spectrum calculated in this work is the first result of this model for the thyroxine molecule.

Spin-dependent transport properties of a chromium porphyrin-based molecular embedded between two graphene nanoribbon electrodes

RSC Advances ◽  
2014 ◽  
Vol 4 (104) ◽  
pp. 60376-60381 ◽  
Author(s):  
Tong Chen ◽  
Lingling Wang ◽  
Xiaofei Li ◽  
Kaiwu Luo ◽  
Liang Xu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electron Transport ◽  
Transport Properties ◽  
Density Functional ◽  
Theoretical Study ◽  
Graphene Nanoribbon ◽  
Functional Theory ◽  
Spin Dependent Transport ◽  
The Density Functional Theory ◽  
Dependent Transport

By using the nonequilibrium Green's function formalism combined with the density-functional theory, we present a theoretical study of the spin-dependent electron transport of a chromium porphyrin-based molecule device.

scholarly journals Energetic and Electronic Properties of NH3, NO2 and SO2 Interacting with GaN Nanotube: A DFT Study

2021 ◽  
Author(s):  
Andrew A. J. Anchieta da Silva ◽  
Caio Vinícius Caetano ◽  
Silvete Guerini
Keyword(s):  
Density Functional Theory ◽  
Stability Analysis ◽  
Air Pollutants ◽  
Chemical Process ◽  
Density Functional ◽  
Energy Gap ◽  
Simulation Software ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
The Stability

Abstract In this work, the interaction of GaN nanotube (GaNNT) with common air pollutants of industrialized cities, such as NH3, NO2 and SO2 in different configurations was studied. For this study, the single-walled (10,0) GaNNT was used. The analysis was done via the density functional theory implemented in the SIESTA simulation software. The analysis of the results shows that the air pollutants alter the properties of nanotubes when they interact with them. The stability analysis shows that the most stable configurations are those in which adsorption occurs through a chemical process. The systems remain semiconductors, but in the case of NO2 and SO2 molecules interacting with GaNNT, there was a significant reduction in the energy gap. Our results also indicate that GaNNT is a promising material to detect and remove NH3 and NO2 molecules from the environment, however it may be not applicable to detect or remove SO2, because the latter interacts strongly with the nanotube, which prevents the GaNNT from being reused.

scholarly journals Metallic and intra-band investigation of optical properties for Borophene nano-sheet: a DFT study

2019 ◽  
Vol 10 (1) ◽  
pp. 33-41
Author(s):  
T. Abasi ◽  
A. Boochani ◽  
S. R. Masharian
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Band Structure ◽  
Density Functional ◽  
Incident Light ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Semiconductor Behavior ◽  
Structure Density ◽  
Theory Framework

AbstractIn this paper, using the density functional theory framework with the FP-LAPW + lo method by GGA approximation, the electronic and optical properties such as band structure, density of states, dielectric function, energy loss function, absorption and reflection have been investigated for borophene nano-sheet. The optical properties of the borophene have been changed as the incident light direction whereas has the metallic and semiconductor behavior, in the borophene sheet and perpendicular light angles, respectively. Therefore, it can be said that the optical properties of this material are anisotropic.

A molecular device providing a remarkable spin filtering effect due to the central molecular stretch caused by lateral zigzag graphene nanoribbon electrodes

2020 ◽  
Vol 22 (12) ◽  
pp. 6755-6762 ◽  
Author(s):  
Xiaoyue Liu ◽  
Jueming Yang ◽  
Xingwu Zhai ◽  
Hongxia Yan ◽  
Yanwen Zhang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Graphene Nanoribbon ◽  
Molecular Devices ◽  
Molecular Device ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Filtering Effect ◽  
Spin Filtering

Through the density functional theory, we studied molecular devices composed of single tetrathiafulvalene (TTF) molecules connected with zigzag graphene nanoribbon electrodes by four different junctions.

scholarly journals Electron-phonon interaction in In-induced √7 ×√3 structures on Si(111) from first-principles

2021 ◽  
Author(s):  
I. Yu. Sklyadneva ◽  
Rolf Heid ◽  
Pedro Miguel Echenique ◽  
Evgueni Chulkov
Keyword(s):  
Density Functional Theory ◽  
Double Layer ◽  
First Principles ◽  
Linear Response ◽  
Density Functional ◽  
Single Layer ◽  
Phonon Interaction ◽  
Functional Theory ◽  
Electron Phonon Interaction ◽  
The Density Functional Theory

Electron-phonon interaction in the Si(111)-supported rectangular √(7 ) ×√3 phases of In is investigated within the density-functional theory and linear-response. For both single-layer and double-layer √(7 ) ×√3 structures, it...

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