Dispersion corrected interaction of polar and nonpolar fluids confined within carbon nanotubes: Density functional theoretical analysis using Grimme's D3 scheme

2017 ◽  
Vol 118 (14) ◽  
pp. e25578 ◽  
Author(s):  
Pooja Sahu ◽  
Sk. Musharaf Ali
Keyword(s):  
Carbon Nanotubes ◽  
Theoretical Analysis ◽  
Density Functional ◽  
Nonpolar Fluids

Quantum Mechanical Investigation of Geometrical Structure and Dynamic Behavior of h-BNNT (9,9-5) and h-AlNNT (9,9-5)Single-Walled Nanotubes: NBO Analysis

2019 ◽  
Vol 16 (9) ◽  
pp. 705-717
Author(s):  
Mehrnoosh Khaleghian ◽  
Fatemeh Azarakhshi
Keyword(s):  
Carbon Nanotubes ◽  
Density Functional ◽  
Structural Parameters ◽  
Energy Levels ◽  
Nbo Analysis ◽  
Electronic Energy ◽  
Boron Nitride Nanotubes ◽  
Basis Set ◽  
B3lyp Method ◽  
Mechanical Investigation

In the present research, B45H36N45 Born Nitride (9,9) nanotube (BNNT) and Al45H36N45 Aluminum nitride (9,9) nanotube (AlNNT) have been studied, both having the same length of 5 angstroms. The main reason for choosing boron nitride nanotubes is their interesting properties compared with carbon nanotubes. For example, resistance to oxidation at high temperatures, chemical and thermal stability higher rather than carbon nanotubes and conductivity in these nanotubes, unlike carbon nanotubes, does not depend on the type of nanotube chirality. The method used in this study is the density functional theory (DFT) at Becke3, Lee-Yang-Parr (B3LYP) method and 6-31G* basis set for all the calculations. At first, the samples were simulated and then the optimized structure was obtained using Gaussian 09 software. The structural parameters of each nanotube were determined in 5 layers. Frequency calculations in order to extract the thermodynamic parameters and natural bond orbital (NBO) calculations have been performed to evaluate the electron density and electrostatic environment of different layers, energy levels and related parameters, such as ionization energy and electronic energy, bond gap energy and the share of hybrid orbitals of different layers.

scholarly journals Phonons in Short-Period GaN/AlN Superlattices: Group-Theoretical Analysis, Ab initio Calculations, and Raman Spectra

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 286
Author(s):  
Valery Davydov ◽  
Evgenii Roginskii ◽  
Yuri Kitaev ◽  
Alexander Smirnov ◽  
Ilya Eliseyev ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Raman Spectra ◽  
Density Functional ◽  
Structural Characteristics ◽  
Vibrational Modes ◽  
Phonon Modes ◽  
Short Period ◽  
Group Theoretical Analysis

We report the results of experimental and theoretical studies of phonon modes in GaN/AlN superlattices (SLs) with a period of several atomic layers, grown by submonolayer digital plasma-assisted molecular-beam epitaxy, which have a great potential for use in quantum and stress engineering. Using detailed group-theoretical analysis, the genesis of the SL vibrational modes from the modes of bulk AlN and GaN crystals is established. Ab initio calculations in the framework of the density functional theory, aimed at studying the phonon states, are performed for SLs with both equal and unequal layer thicknesses. The frequencies of the vibrational modes are calculated, and atomic displacement patterns are obtained. Raman spectra are calculated and compared with the experimental ones. The results of the ab initio calculations are in good agreement with the experimental Raman spectra and the results of the group-theoretical analysis. As a result of comprehensive studies, the correlations between the parameters of acoustic and optical phonons and the structure of SLs are obtained. This opens up new possibilities for the analysis of the structural characteristics of short-period GaN/AlN SLs using Raman spectroscopy. The results obtained can be used to optimize the growth technologies aimed to form structurally perfect short-period GaN/AlN SLs.

Molecular Vibration Theoretical Analysis of Two-Dimensional Photoelectric Conversion Material WSe2

2018 ◽  
Vol 765 ◽  
pp. 16-23
Author(s):  
Rui Zhang ◽  
Hong Bo Li ◽  
Guo Qiang Hao ◽  
Wen Bo Liu ◽  
Xiao Jun Ye ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Density Functional ◽  
Molecular Vibration ◽  
Raman Shift ◽  
Vibration Modes ◽  
Photoelectric Conversion ◽  
Functional Theory ◽  
Conversion Materials ◽  
Direct Band ◽  
New Generation

Monolayer WSe2is flexible, nearly transparent and direct band-gap semiconductor with the potential to be new generation thin film photoelectric conversion materials. The molecule vibration modes of monolayer and bulk WSe2was analyzed by factor group and the phonons dispersion and vibration frequency was calculated by first-principles based on density functional theory. Furthermore, the comparison between the above calculations and experiment values of Raman shift of monolayer and bulk WSe2was made to verify the accuracy of theoretical analysis and theoretically explain the differences of monolayer and bulk WSe2materials in Raman spectra.

Density Functional Theoretical Analysis of the Molecular Structural Effects on Raman Spectra ofβ-Carotene and Lycopene

2012 ◽  
Vol 30 (10) ◽  
pp. 2573-2580 ◽  
Author(s):  
Weilong Liu ◽  
Zhigang Wang ◽  
Zhiren Zheng ◽  
Lilin Jiang ◽  
Yanqiang Yang ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Raman Spectra ◽  
Density Functional ◽  
Structural Effects

Density-Functional Theory Studies of Step-Kinked Carbon Nanotubes

2011 ◽  
Vol 115 (10) ◽  
pp. 4235-4239 ◽  
Author(s):  
Xiaojun Wu ◽  
Rulong Zhou ◽  
Jinlong Yang ◽  
Xiao Cheng Zeng
Keyword(s):  
Carbon Nanotubes ◽  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory
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