scholarly journals Design pollution gas sensor using graphene ribbon: density function theory (DFT)

2022 ◽  
Vol 54 (1) ◽  
Author(s):  
Ruaa. S. Al-Hasnawy ◽  
Ali S. Shaker ◽  
Muntather H. Albosaabar ◽  
Zahraa A. AlMaamouri ◽  
Hamed A. Al-taee
2021 ◽  
Author(s):  
Ruaa.S. Al-Hasnawy ◽  
Ali S. Shaker ◽  
Muntather H Albosaabar ◽  
Zahraa A. Al-Maamouri ◽  
Hamed A. Al-taee

Abstract Density Function theory (DFT) calculation used to employed ground and excitation states for graphene ribbons, types of adsorption, energy gap, maximum wave length and optical band gap. Adsorption energy showed that CO2 gas molecule have chemical adsorption in distance 1 and 1.5 Angstrom, distance 2 and 2.5 Angstrom appear physical adsorption, adsorption energy decreased when distance between surface and gas molecule increasing. Resulting from chemical adsorption energy gap change with distance 1 and 1.5 Angstrom because attract gas molecule with surface. Excitation energy for nano system in sample 1 and 4 shifted to low wavelength (blue shift) change from 1018 nm to 993 nm and 718 nm on series. Other sample have red shift and energy gap becoming open. Result showed that graphene ribbon sense carbon dioxide gas (CO2).


2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Madhumita Hazra ◽  
Tanushree Dolai ◽  
Akhil Pandey ◽  
Subrata Kumar Dey ◽  
Animesh Patra

The photo physical properties of two mononuclear pentacoordinated copper(II) complexes formulated as [Cu(L)(Cl)(H2O)] (1) and [Cu(L)(Br)(H2O)] (2)HL = (1-[(3-methyl-pyridine-2-ylimino)-methyl]-naphthalen-2-ol) were synthesized and characterized by elemental, physicochemical, and spectroscopic methods. The density function theory calculations are used to investigate the electronic structures and the electronic properties of ligand and complex. The interactions of copper(II) complexes towards calf thymus DNA were examined with the help of absorption, viscosity, and fluorescence spectroscopic techniques at pH 7.40. All spectroscopy's result indicates that complexes show good binding activity to calf thymus DNA through groove binding. The optical absorption and fluorescence emission properties of microwires were characterized by fluorescence microscope. From a spectroscopic viewpoint, all compounds strongly emit green light in the solid state. The microscopy investigation suggested that microwires exhibited optical waveguide behaviour which are applicable as fluorescent nanomaterials and can be used as building blocks for miniaturized photonic devices. Antibacterial study reveals that complexes are better antimicrobial agents than free Schiff base due to bacterial cell penetration by chelation. Moreover, the antioxidant study of the ligand and complexes is evaluated by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical assays, which demonstrate that the complexes are of higher antioxidant activity than free ligand.


2011 ◽  
Vol 221 ◽  
pp. 180-183 ◽  
Author(s):  
Jian Li ◽  
Xun Zhang Yu ◽  
Kai Zhang

The ring-opening reaction between bisphenol A and epichlorohydrin was calculated by Gaussian03. The Density Function Theory (DFT) method were employed to study the geometry structures of bisphenol A and epichlorohydrin and the product was obtained on the base of B3LYP/6-31G+ model in this paper. The transitional states (Ts1, Ts2) during the ring-opening process were found by TS method and the energy changing of the system was proved by IRC calculation. Results showed that the energy reduced by 64.37726kJ/mol during the ring-opening process. The product was confirmed to be thermodynamically stable.


2021 ◽  
Vol 91 (5) ◽  
pp. 828-834
Author(s):  
K. V. Zaitsev ◽  
A. Yu. Oprunenko ◽  
I. P. Gloriozov ◽  
M. S. Nechaev ◽  
Yu. F. Oprunenko ◽  
...  

2011 ◽  
Vol 36 (4) ◽  
pp. 323-328
Author(s):  
Yiling Bei ◽  
Qingyang Liu

The reaction of silylene with acetylene was observed by the density function theory (DFT) method at the 6 - 311 g (d,p) level. A new reaction pathway has been identified involving the tetra-conjugated: SiH2CH==CHH2Si:. Thermodynamic and kinetic analysis confirms the reaction to be spontaneous at room temperature. The new intermediate proposed in this work offers a resolution of the conundrum of the silylene/acetylene reaction.


Author(s):  
Cui Zhou ◽  
Ding Haonan ◽  
Yu Feng

A new subfamily of Heusler alloys, i.e. double half-Heusler alloys Mn2CoCrZ2 (Z=P, As), are investigated by employing the density function theory combined with the nonequilibrium Green’s function. The calculations on...


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