scholarly journals Termination Effects in Aluminosilicate and Aluminogermanate Imogolite Nanotubes: A Density Functional Theory Study

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1051
Author(s):  
Emiliano Poli ◽  
Joshua D. Elliott ◽  
Ziwei Chai ◽  
Gilberto Teobaldi
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Finite Size ◽  
Relative Energy ◽  
Finite Model ◽  
Functional Theory ◽  
Band Bending ◽  
Longitudinal Effects ◽  
Screening And Identification ◽  
Dft Simulations

We investigate termination effects in aluminosilicate (AlSi) and aluminogermanate (AlGe) imogolite nanotubes (NTs) by means of semi-local and range-corrected hybrid Density Functional Theory (DFT) simulations. Following screening and identification of the smallest finite model capable of accommodating full relaxation of the NT terminations around an otherwise geometrically and electrostatically unperturbed core region, we quantify and discuss the effects of physical truncation on the structure, relative energy, electrostatics and electronic properties of differently terminated, finite-size models of the NTs. In addition to composition-dependent changes in the valence (VB) and conduction band (CB) edges and resultant band gap (BG), the DFT simulations uncover longitudinal band bending and separation in the finite AlSi and AlGe models. Depending on the given termination of the NTs, such longitudinal effects manifest in conjunction with the radial band separation typical of fully periodic AlSi and AlGe NTs. The strong composition dependence of the longitudinal and radial band bending in AlSi and AlGe NTs suggests different mechanisms for the generation, relaxation and separation of photo-generated holes in AlSi and AlGe NTs, inviting further research in the untapped potential of imogolite compositional and structural flexibility for photo-catalytic applications.

Effect of Hf doping on He behavior in Tritium storage material ZrCo

2021 ◽  
Author(s):  
Xianggang Kong ◽  
You Yu ◽  
yanhong shen ◽  
Jiangfeng Song
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Storage Material ◽  
Functional Theory ◽  
Dft Simulations ◽  
Tritium Storage

An exhaustive analysis based on density functional theory (DFT) simulations of the effect of the Hf doping on the helium behavior has been performed in ZrCo. The He impurities have...

scholarly journals Electronic properties of the coronene series from thermally-assisted-occupation density functional theory

RSC Advances ◽  
2018 ◽  
Vol 8 (60) ◽  
pp. 34350-34358 ◽  
Author(s):  
Chia-Nan Yeh ◽  
Can Wu ◽  
Haibin Su ◽  
Jeng-Da Chai
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Finite Size ◽  
Comprehensive Understanding ◽  
Functional Theory ◽  
Graphene Flakes

To fully utilize the great potential of graphene in electronics, a comprehensive understanding of the electronic properties of finite-size graphene flakes is essential.

scholarly journals Assessing Density Functional Theory Approaches for Predicting the Structure and Relative Energy of Salicylideneaniline Molecular Switches in the Solid State

2017 ◽  
Vol 121 (12) ◽  
pp. 6898-6908 ◽  
Author(s):  
Jean Quertinmont ◽  
Andrea Carletta ◽  
Nikolay A. Tumanov ◽  
Tom Leyssens ◽  
Johan Wouters ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Density Functional ◽  
Molecular Switches ◽  
Relative Energy ◽  
Functional Theory

scholarly journals Zirconocene-Catalyzed Dimerization of α-Olefins: DFT Modeling of the Zr-Al Binuclear Reaction Mechanism

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3565 ◽  
Author(s):  
Ilya Nifant’ev ◽  
Alexander Vinogradov ◽  
Alexey Vinogradov ◽  
Stanislav Karchevsky ◽  
Pavel Ivchenko
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Molecular Hydrogen ◽  
Density Functional ◽  
Effective Agent ◽  
Functional Theory ◽  
Dft Simulation ◽  
Dft Modeling ◽  
Dft Simulations

Zirconocene-mediated selective dimerization of α-olefins usually occurs when precatalyst (η5-C5H5)2ZrCl2 is activated by minimal excess of methylalumoxane (MAO). In this paper, we present the results of density functional theory (DFT) simulation of the initiation, propagation, and termination stages of dimerization and oligomerization of propylene within the framework of Zr-Al binuclear mechanism at M-06x/DGDZVP level of theory. The results of the analysis of the reaction profiles allow to explain experimental facts such as oligomerization of α-olefins at high MAO/(η5-C5H5)2ZrCl2 ratios and increase of the selectivity of dimerization in the presence of R2AlCl. The results of DFT simulations confirm the crucial role of the presence of chloride in the selectivity of dimerization. The molecular hydrogen was found in silico and proven experimentally as an effective agent that increases the rate and selectivity of dimerization.

Density functional theory study of bis(imino) N-heterocyclic carbene iron(II) complexes

2014 ◽  
Vol 92 (10) ◽  
pp. 925-931 ◽  
Author(s):  
Jameel Al Thagfi ◽  
Gino G. Lavoie
Keyword(s):  
Density Functional Theory ◽  
Electron Density ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Iron Complexes ◽  
Relative Energy ◽  
Iron Complex ◽  
Geometrical Parameters ◽  
Functional Theory ◽  
Imine Group

Density functional theory calculations at the B3LYP/DGDZVP and UB3LYP/TZVP levels were performed on 1,3-bis[1-(2,6-dimethylphenylimino)ethyl]imidazolium and on the corresponding imidazol-2-ylidene iron(II) dichloride complex, respectively. The resulting geometrical parameters of the optimized structures were in good agreement with previously reported X-ray structures. The ground state for the high-spin (quintet multiplicity) iron complex is 82.4 kJ/mol lower in energy compared to the low-spin (triplet) configuration, in agreement with magnetic susceptibility measurements. Further calculations were carried out on related benzimidazol-2-ylidene and pyrimidin-2-ylidene ligands and on the corresponding iron complexes to gain insight into their electronic properties and reactivities. The energy of the highest occupied and lowest unoccupied molecular orbitals of all three carbenes suggests that the pyrimidin-2-ylidene and the benzimidazol-2-ylidene are the best σ-donor and best π-acceptor, respectively. Using those results, the metal center in the pyrimidin-2-ylidene iron dichloride complex was predicted to bear the highest electron density. This was supported by the high relative energy of its highest occupied molecular orbital compared to that of the corresponding imidazole-2-ylidene and benzimidazol-2-ylidene iron complexes. The electrostatic potential maps of all three metal complexes furthermore indicated a marked decrease in electron density for the coordinated imine group, supporting a greater reactivity towards nucleophiles.

Ab Initio Theoretical Studies of Relative Stabilities and IR Spectrum of 5-Methylcytosine Tautomers

2003 ◽  
Vol 2003 (4) ◽  
pp. 195-199 ◽  
Author(s):  
Lida Ghassemzadeh ◽  
Majid Monajjemi ◽  
Karim Zare
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Relative Energy ◽  
Theoretical Studies ◽  
Functional Theory ◽  
Relative Stabilities ◽  
B3lyp Method ◽  
Wide Range ◽  
Good Agreement

The structure and relative energies of the tautomers of 5-methylcytosine in the gasphase and in different solvents are predicted using MP2 and density functional theory methods. The order of stability for these tautomers is C3>C1>C2>C4>C5>C6 calculated by MP2 and C1>C3>C2>C4>C5>C6 calculated by the B3LYP method. Relative energy calculations are performed in wide range of solvent dielectrics and in all solvents the oxo-amino C1 is predicted as the most stable tautomer. The infrared spectra of two dominant tautomers are calculated in the gas phase using HF and density functional theory. Good agreement between calculated (DFT) and experimental harmonic vibrational frequencies is found.

A density functional theory study on the underwater adhesion of catechol onto a graphite surface

2021 ◽  
Author(s):  
Ramesh Kumar Chitumalla ◽  
Kiduk Kim ◽  
Xingfa Gao ◽  
Joonkyung Jang
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Silica Surface ◽  
Graphite Surface ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Wet Adhesion ◽  
Underwater Adhesion ◽  
Dft Simulations ◽  
Periodic Dft

By employing periodic-DFT simulations, we unveil that the wet adhesion of mussels onto a hydrophobic graphite surface is significantly strong and is comparable with that on a hydrophilic silica surface.

scholarly journals DENSITY FUNCTIONAL THEORY (DFT) SIMULATIONS OF SHOCKED LIQUID XENON

2009 ◽  
Author(s):  
Thomas R. Mattsson ◽  
Rudolph J. Magyar ◽  
Mark Elert ◽  
Michael D. Furnish ◽  
William W. Anderson ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Liquid Xenon ◽  
Functional Theory ◽  
Dft Simulations
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