Structural Shifting and Electronic Properties of Stone-Wales Defect in Armchair Edge (5,5) Carbon Nanotube

2013 ◽  
Vol 772 ◽  
pp. 380-385 ◽  
Author(s):  
Supri Jadi ◽  
A. Setiadi
Keyword(s):  
Carbon Nanotube ◽  
Density Functional ◽  
Minimum Energy ◽  
Elastic Band ◽  
Functional Theory ◽  
Barrier Energy ◽  
Wales Defect ◽  
The Density Functional Theory ◽  
Calculation Results ◽  
Nudge Elastic Band

Stone Wales (SW) defect is one type of topological defect on the CNT, in this study we performed first principles calculations of SW defects in armchair edge (5,5) carbon nanotube (CNT) by the density functional theory (DFT). Two different defects were studied such as longitudinal and circumference types. Our calculation results show that a longitudinal SW defect is more stable than circumference SW defect. However barrier energy as parameter to control the SW defect in CNT was studied, in calculation we applied Nudge Elastic Band (NEB) method to find minimum energy path (MEP) and barrier energy for SW defect transitions. The result shows that barrier energy of circumference SW defect is lower than another one. We also found that in the case of circumference SW defect, armchair edge (5,5) CNT become semiconductor with the band gap of 0.0544 eV.

The effect of defects on the catalytic activity of single Au atom supported carbon nanotubes and reaction mechanism for CO oxidation

2017 ◽  
Vol 19 (33) ◽  
pp. 22344-22354 ◽  
Author(s):  
Sajjad Ali ◽  
Tian Fu Liu ◽  
Zan Lian ◽  
Bo Li ◽  
Dang Sheng Su
Keyword(s):  
Carbon Nanotubes ◽  
Density Functional Theory ◽  
Catalytic Activity ◽  
Carbon Nanotube ◽  
Reaction Mechanism ◽  
Co Oxidation ◽  
Density Functional ◽  
Functional Theory ◽  
Single Walled Carbon Nanotube ◽  
Wales Defect

The mechanism of CO oxidation by O2 on a single Au atom supported on pristine, mono atom vacancy (m), di atom vacancy (di) and the Stone Wales defect (SW) on single walled carbon nanotube (SWCNT) surface is systematically investigated theoretically using density functional theory.

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.

Conformation and electronic structure of Carbidopa. A QM/MD study

2016 ◽  
Vol 15 (01) ◽  
pp. 1650002
Author(s):  
Ghader M. Sukker ◽  
Nuha Wazzan ◽  
Ashour Ahmed ◽  
Rifaat Hilal
Keyword(s):  
Density Functional ◽  
Minimum Energy ◽  
Geometry Optimization ◽  
Md Simulations ◽  
Energy Structure ◽  
Functional Theory ◽  
Conformational Preferences ◽  
The Density Functional Theory ◽  
Quantum Chemical Topology ◽  
Bonding Characteristics

Carbidopa (CD) is a drug used in combination with L-dopa (LD) in treatment of Parkinson’s disease (PD). CD is an inhibitor for enzyme decarboxylase, yet its mode of action is not entirely known although it is believed to involve enzyme shape recognition. The present work attempts to investigate the conformational preferences of CD. Tight geometry optimization at the density functional theory (DFT)/B3LYP/6-311[Formula: see text]G** level of theory has been carried out. The shallow nature of the potential energy surface (PES) and the presence of several local minima within a small energy range necessitate the launching of DFT-based molecular dynamics (MD) simulations. Two MD experiments were submitted for 35,000 points each. The complete trajectory in time domain of 10.5 ps is analyzed and discussed. The global minimum energy structure of CD is localized and identified by subsequent frequency calculations. The quantum theory of atom in molecules (QTAIMs) is used to extract and compare the quantum chemical topology features of the electron density distribution in CD and LD. Bonding characteristics are analyzed and discussed within the natural bond orbital (NBO) framework.

scholarly journals Investigation of the absorption of CO2 in ionic liquid

2016 ◽  
Vol 29 (1) ◽  
pp. 41-46
Author(s):  
Kalyan Dhar ◽  
Syed Fahim
Keyword(s):  
Ionic Liquid ◽  
Binding Sites ◽  
Density Functional ◽  
Room Temperature ◽  
Minimum Energy ◽  
Environmental Concerns ◽  
Co2 Absorption ◽  
Solvation Model ◽  
Functional Theory ◽  
The Density Functional Theory

Due to environmental concerns, current interest is the development of technologies that may be able to remove CO2 efficiently from exhaust gases and thus avoid its dispersion in the atmosphere. The density functional theory (DFT) calculations with the modern continuum solvation model (IEFPCM-SMD) was used to study the mechanism of CO2 absorption in room temperature ionic liquid such as, [EMIM][BF4] (1-ethyl-3- methylimidazolium tetrafluoroborate). We determine the minimum energy structures and to determine the possible binding sites for CO2 absorption process in [EMIM][BF4]; by comparing the relative minimum energy of [EMIM][BF4] in the presence and absence of CO2.Bangladesh J. Sci. Res. 29(1): 41-46, June-2016

Study of Elastic Properies of Ti3Al Intermetallic Compound Using the Ab Initio Calculation

2014 ◽  
Vol 805 ◽  
pp. 690-693
Author(s):  
Carlos Alberto Soufen ◽  
Marcelo Capella de Campos ◽  
Carlos Alberto Fonzar Pintão ◽  
Momotaro Imaizumi
Keyword(s):  
Intermetallic Compound ◽  
Elastic Properties ◽  
Density Functional ◽  
Minimum Energy ◽  
Young Modulus ◽  
Lattice Parameter ◽  
Full Potential ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Equilibrium Lattice Parameter

The elastic properties of a Ti3Al intermetallic compound were studied using full potential (FP LAPW ) with the APW+lo method. The FP-LAPW is among the most accurate band structure calculations currently available and is based on the density functional theory with general gradient approximation for the exchange and correlation potential. This method provides the structural properties of the ground state as bulk modulus, equilibrium lattice parameter, and equilibrium minimum energy, and the elastic properties as shear modulus, young modulus, Zener coefficient (anisotropy), and Poisson coefficient. The calculated elastic properties are coherent with the elastic properties of the material.

scholarly journals Electronic and transport properties of carbon and boron-nitride ferrocene nanopeapods

2014 ◽  
Vol 2 (46) ◽  
pp. 10017-10030 ◽  
Author(s):  
Guiling Zhang ◽  
Sun Peng ◽  
Yan Shang ◽  
Zhao-Di Yang ◽  
Xiao Cheng Zeng
Keyword(s):  
Density Functional Theory ◽  
Carbon Nanotube ◽  
Boron Nitride ◽  
Transport Properties ◽  
Density Functional ◽  
Boron Nitride Nanotube ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Non Equilibrium Green’S Function ◽  
Non Equilibrium

Electronic and transport properties of novel ferrocene based carbon nanotube (CNT) and boron-nitride nanotube (BNNT) nanopeapods, including Fe(Cp)2@CNT, Fe2(Cp)3@CNT, Fe(Cp)2@BNNT, and Fe2(Cp)3@BNNT (where Cp refers as cyclopentadiene), are investigated using the density functional theory and non-equilibrium Green's function methods.

scholarly journals A combined DFT/topological analysis approach for modeling disordered solid electrolytes

2019 ◽  
Vol 201 ◽  
pp. 02005 ◽  
Author(s):  
Pavel Zolotarev ◽  
Nadezhda Nekrasova ◽  
Andrey Golov ◽  
Roman Eremin
Keyword(s):  
Density Functional ◽  
Topological Analysis ◽  
Density Functional Theory Calculations ◽  
Topological Descriptors ◽  
Elastic Band ◽  
Functional Theory ◽  
Ion Migration ◽  
Energy Characteristics ◽  
The Density Functional Theory ◽  
Band Method

In the scope of this study, the Ag2S·CdS·3SnS2 solid electrolyte disordered in the Cd/Sn sublattice is explored by means of the approach involving configurational space (CS) setting and first-principles calculations. Within the density functional theory calculations on the CS, the absolute differences in Ag vacancy formation energies up to 2.6 eV/cell were obtained for possible Cd/Sn dispositions. Subsequently, silver ion migration was modeled using the nudged elastic band method. The migration energies in the range of 0.250 to 2.993 eV/cell were obtained. By application of topological descriptors, namely, the relative disposition of Cd atoms and the number of Cd atoms in the vicinity of Ag vacancy, the reliable correlations were obtained between the Cd/Sn relative disposition and the calculated energy characteristics.

scholarly journals The electronic and transport properties of (VBz)n@CNT and (VBz)n@BNNT nanocables

2015 ◽  
Vol 3 (16) ◽  
pp. 4039-4049 ◽  
Author(s):  
Xiu Yan Liang ◽  
Guiling Zhang ◽  
Peng Sun ◽  
Yan Shang ◽  
Zhao-Di Yang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Carbon Nanotube ◽  
Boron Nitride ◽  
Transport Properties ◽  
Electronic Structures ◽  
Density Functional ◽  
Boron Nitride Nanotube ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Non Equilibrium Green’S Function

The electronic structures and transport properties of prototype carbon nanotube (CNT) (10,10) and boron–nitride nanotube (BNNT) (10,10) nanocables, including (VBz)n@CNT and (VBz)n@BNNT (where Bz = C6H6), are investigated using the density functional theory (DFT) and the non-equilibrium Green's function (NEGF) methods.

SIMULATION OF NANOSCALE ETCHING FOR NANOTUBE AND GRAPHENE DEVICES

2012 ◽  
Vol 1451 ◽  
pp. 21-24
Author(s):  
Koichi Kusakabe
Keyword(s):  
Hydrogen Atom ◽  
Density Functional ◽  
Carbon Materials ◽  
Tube Wall ◽  
Hydrogen Atoms ◽  
Functional Theory ◽  
Wales Defect ◽  
The Density Functional Theory ◽  
Graphene Devices ◽  
Tungsten Tip

ABSTRACTIn order to find an efficient method to etch nano-carbon materials by hydrogenation in a controlled manner, we have studied hydrogen-atom adsorption on various deformed nanotubes using computer simulations based on the density-functional theory. The nanotube with an atomic lack is compared to a deformed tube with the Stone-Wales defect and a twisted tube wall. Similar to the known experimental etching condition for graphene, an atomic lack is effective to accumulate hydrogen atoms around the defect. Compared to the flat graphene, however, nanotube walls with curvature allow on-top adsorption of a hydrogen atom and selectivity in the hydrogenated site becomes worse. To achieve a controlled etching process, usage of a tungsten tip which realizes focused hydrogenation is proposed for natotubes and curved graphene.

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.

Sign in / Sign up

Export Citation Format

Share Document