Why and How the Zigzag Edge of Suspended Graphene Sheet where Deformed

2013 ◽  
Vol 829 ◽  
pp. 204-207
Author(s):  
Behrad Barakati ◽  
Ahmad Yazdani ◽  
Farhang Soheilian ◽  
Mahdi Ghazanfari
Keyword(s):  
Carbon Atom ◽  
Graphene Sheet ◽  
Electron Density ◽  
Density Functional ◽  
Zigzag Chain ◽  
Zigzag Edge ◽  
Functional Theory ◽  
Electron Density Gradient ◽  
True Edge ◽  
Structure Density

The edge of graphene plays an important role in electronic and spintronic properties of graphene. As we know in many article zigzag edge used as stable edge but this edge cannot be true edge. When the graphene sheet is cut, bonds are broken along this line and electrons that participate in bond be free, so there is electron density gradient along the edge. Because of this the carbon atoms along the edge is moved till the stable structure be established. For achieving to this specific structure, density functional theory was used via Gaussian package. The result shows hexagons on the edge are going to deform to pentagon and heptagon by change the kind of bond in this chain. In the other zigzag chain behind the edge we have movement of electron density from one carbon atom to another carbon atom by help of carbon atom that placed between them. So we suggested new edge that can be replacement by zigzag edge in calculation with more less structure energy that identify in experiment method too.

scholarly journals First-principle calculations for electronic structure and bonding properties in layered Na2Ti3O7

Open Physics ◽  
2011 ◽  
Vol 9 (6) ◽  
Author(s):  
Yongliang An ◽  
Zhonghua Li ◽  
Hongping Xiang ◽  
Yongjiang Huang ◽  
Jun Shen
Keyword(s):  
Electronic Structure ◽  
Electron Density ◽  
Density Functional ◽  
Exchange Property ◽  
Strong Interactions ◽  
Functional Theory ◽  
Bonding Properties ◽  
Structure And Bonding ◽  
Structure Density ◽  
The Stability

AbstractFirst-principles calculations of Na2Ti3O7 have been carried out with density-functional theory (DFT) and ultrasoft pseudopotentials. The electronic structure and bonding properties in layered Na2Ti3O7 have been studied through calculating band structure, density of states, electron density, electron density difference and Mulliken bond populations. The calculated results reveal that Na2Ti3O7 is a semiconductor with an indirect gap and exhibits both ionic and covalent characters. The stability of the (Ti3O7)2− layers is attributed to the covalent bonding of strong interactions between O 2p and Ti 3d orbitals. Furthermore, the O atoms located in the innerlayers interact more strongly with the neighboring Ti atoms than those in the interlayer regions. The ion-exchange property is due to the ionic bonding between the Na+ and (Ti3O7)2− layers, which can stabilize the interlayers of layered Na2Ti3O7 structure.

scholarly journals Influence of Copper(I) Halides on the Reactivity of Aliphatic Carbodiimides

2020 ◽  
Vol 3 (1) ◽  
pp. 20
Author(s):  
Valentina Ferraro ◽  
Marco Bortoluzzi
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
General Formula ◽  
Electron Density ◽  
Density Functional ◽  
Functional Theory ◽  
Fukui Functions ◽  
Bond Lengths ◽  
Linear Complexes ◽  
Nitrogen Bond

The influence of copper(I) halides CuX (X = Cl, Br, I) on the electronic structure of N,N′-diisopropylcarbodiimide (DICDI) and N,N′-dicyclohexylcarbodiimide (DCC) was investigated by means of computational DFT (density functional theory) methods. The coordination of the considered carbodiimides occurs by one of the nitrogen atoms, with the formation of linear complexes having a general formula of [CuX(carbodiimide)]. Besides varying the carbon–nitrogen bond lengths, the thermodynamically favourable interaction with Cu(I) reduces the electron density on the carbodiimides and alters the energies of the (NCN)-centred, unoccupied orbitals. A small dependence of these effects on the choice of the halide was observable. The computed Fukui functions suggested negligible interaction of Cu(I) with incoming nucleophiles, and the reactivity of carbodiimides was altered by coordination mainly because of the increased electrophilicity of the {NCN} fragments.

Understanding the molecular mechanism of the stereoselective conversion of N-trialkylsilyloxy nitronates into bicyclic isoxazoline derivatives

2021 ◽  
Author(s):  
Agnieszka Kącka-Zych ◽  
Radomir Jasinski
Keyword(s):  
Density Functional Theory ◽  
Molecular Mechanism ◽  
Electron Density ◽  
Density Functional ◽  
Dft Method ◽  
Functional Theory ◽  
Molecular Electron ◽  
Molecular Electron Density Theory

Conversion of N-trialkylsilyloxy nitronates into bicyclic isoxazoline derivatives has been explored using Density Functional Theory (DFT) method within the context of the Molecular Electron Density Theory (MEDT) at the B97XD(PCM)/6-311G(d,p)...

Developing orbital-free quantum crystallography: the local potentials and associated partial charge densities

2021 ◽  
Vol 77 (4) ◽  
Author(s):  
Vladimir Tsirelson ◽  
Adam Stash
Keyword(s):  
Density Functional Theory ◽  
Electron Density ◽  
Density Functional ◽  
Electronic Energy ◽  
Physical Content ◽  
Functional Theory ◽  
Orbital Free ◽  
The One ◽  
Physical And Chemical ◽  
Quantum Crystallography

This work extends the orbital-free density functional theory to the field of quantum crystallography. The total electronic energy is decomposed into electrostatic, exchange, Weizsacker and Pauli components on the basis of physically grounded arguments. Then, the one-electron Euler equation is re-written through corresponding potentials, which have clear physical and chemical meaning. Partial electron densities related with these potentials by the Poisson equation are also defined. All these functions were analyzed from viewpoint of their physical content and limits of applicability. Then, they were expressed in terms of experimental electron density and its derivatives using the orbital-free density functional theory approximations, and applied to the study of chemical bonding in a heteromolecular crystal of ammonium hydrooxalate oxalic acid dihydrate. It is demonstrated that this approach allows the electron density to be decomposed into physically meaningful components associated with electrostatics, exchange, and spin-independent wave properties of electrons or with their combinations in a crystal. Therefore, the bonding information about a crystal that was previously unavailable for X-ray diffraction analysis can be now obtained.

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