DFT Study of Alkynyl Porphyrin Dimers and Brominated Tetraphenyl Porphyrins

1997 ◽  
Vol 479 ◽  
Author(s):  
Zhiqiang Wang ◽  
Paul Day ◽  
Ruth Pachter ◽  
Daniel G. McLean
Keyword(s):  
Density Functional ◽  
Electronic Structure Calculations ◽  
Planar Geometry ◽  
Porphyrin Ring ◽  
Functional Theory ◽  
Acetylene Group ◽  
Homo And Lumo ◽  
Homo Lumo ◽  
Structure Calculations ◽  
Porphyrin Dimers

AbstractGeometry optimizations and electronic structure calculations using Density Functional Theory (DFT) are reported for tetra-acetylene porphyrins (TAP), their dimers, and octabromotetraphenyl porphyrins (OBP). The acetylene group contributes to the π-electron conjugation along the porphyrin ring for the HOMO and LUMO, and reduces significantly the HOMO-LUMO gap. The gap is further reduced in dimers. The planar geometry of the TAP dimer has a lower energy than the non-planar one. The geometry of H2OBP is found to be non-planar, and the distortion of porphyrin ring is shown to be closely related to the HOMO-LUMO gap.

A comprehensive investigation of the intermolecular interactions between CH2N2 and X12Y12 (X = B, Al, Ga; Y = N, P, As) nanocages

2021 ◽  
pp. 1-9
Author(s):  
Mohsen Doust Mohammadi ◽  
Hewa Y. Abdullah ◽  
Somnath Bhowmick ◽  
George Biskos
Keyword(s):  
Density Functional ◽  
Adsorption Process ◽  
Building Blocks ◽  
Electronic Structure Calculations ◽  
Comprehensive Investigation ◽  
Functional Theory ◽  
Strong Bond ◽  
Homo And Lumo ◽  
A Charge ◽  
Structure Calculations

In this paper, we have theoretically determined the possibility of adsorption of the gaseous CH2N2 molecule on the surface of X12Y12 nanocages, where X = B, Al, Ga and Y = N, P, As. The electronic structure calculations have been performed by density functional theory (DFT) using four functionals (i.e., B3LYP-D3, M06-2X, ωB97XD, and CAM-B3LYP), together with the 6-311G(d) basis function. We find that the adsorption of CH2N2 on top of the X–Y bond of the nanocage is the most preferred site for adsorption. The adsorption process is accompanied by a charge-transfer phenomenon, which results in a strong bond between the terminal N atom of diazomethane and the X atom of the nanocage. This gives rise to significant changes in the highest and lowest occupied molecular orbital (HOMO and LUMO, respectively) energies and thus attribute properties to the nanocages that enable them to act as building blocks of CH2N2 sensing materials.

scholarly journals Molecular structure, NBO analysis, first hyper polarizability, and homo-lumo studies of π-extended tetrathiafulvalene (EXTTF) derivatives connected to π-nitro phenyl by density functional method

2018 ◽  
Vol 6 (1) ◽  
pp. 114
Author(s):  
Tahar Abbaz ◽  
Amel Bendjeddou ◽  
Didier Villemin
Keyword(s):  
Density Functional ◽  
Density Functional Method ◽  
Nbo Analysis ◽  
Functional Method ◽  
Total Charge ◽  
Linear Optics ◽  
Functional Theory ◽  
Non Linear Optics ◽  
Homo And Lumo ◽  
Homo Lumo

In these study we have been obtained the structural properties of (exTTF) derivatives 1-4 by using B3LYP/6-31G(d,p) of Density Functional Theory (DFT) utilizing Becke three exchange functional and Lee Yang Paar correlation functional. The calculation of first hyperpolarizability shows that the molecules are attractive molecules for future applications in non-linear optics. Molecular electrostatic potential (MEP) at a point in the space around a molecule gives an indication of the net electrostatic effect produced at that point by the total charge distribution of the molecule. The calculated HOMO and LUMO energies show that charge transfer occurs within these molecules. 

Identifying the catalytically active sites on the layered tri-chalcogenide compounds CoPS3 and NiPS3 for efficient hydrogen evolution reaction

2021 ◽  
Author(s):  
Khorsed Alam ◽  
Tisita Das ◽  
Sudip Chakraborty ◽  
Prasenjit Sen
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Density Functional ◽  
Electronic Structure Calculations ◽  
Functional Theory ◽  
Catalytically Active ◽  
Structure Calculations

Electronic structure calculations based on density functional theory are used to identify the catalytically active sites for the hydrogen evolution reaction on single layers of the two transition metal tri-chalcogenide...

Meso-alkynyl corroles and their cobalt(III), manganese(III) and gallium(III) complexes

2020 ◽  
Vol 24 (05n07) ◽  
pp. 737-749
Author(s):  
Michael Haas ◽  
Sabrina Gonglach ◽  
Wolfgang Schöfberger
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Theoretical Study ◽  
Lumo Energy ◽  
Functional Theory ◽  
Energy Gaps ◽  
Peak Broadening ◽  
Homo And Lumo ◽  
Homo Lumo

We report routes towards synthesis of novel [Formula: see text]-conjugated freebase cobalt, copper, gallium and manganese meso-alkynylcorroles. UV-vis spectra show that extensive peak broadening, red shifts, and changes in the oscillator strength of absorptions increase with the extension of [Formula: see text]-conjugation. Using density functional theory (DFT), we have carried out a first theoretical study of the electronic structure of these metallocorroles. Decreased energy gaps of about 0.3–0.4 eV between the HOMO and LUMO orbitals compared to the corresponding copper, gallium and manganese meso-5,10,15 triphenylcorrole are observed. In all cases, the HOMO energies are nearly unperturbed as the [Formula: see text]-conjugation is expanded. The contraction of the HOMO–LUMO energy gaps is attributed to the lowered LUMO energies.

scholarly journals Metallic bands in chevron-type polyacenes

RSC Advances ◽  
2020 ◽  
Vol 10 (56) ◽  
pp. 33844-33850
Author(s):  
Mohammed A. Kher-Elden ◽  
Ignacio Piquero-Zulaica ◽  
Kamel M. Abd El-Aziz ◽  
J. Enrique Ortega ◽  
Zakaria M. Abd El-Fattah
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Expansion Method ◽  
Electronic Structure Calculations ◽  
Plane Wave Expansion ◽  
Plane Wave Expansion Method ◽  
Functional Theory ◽  
Structure Calculations ◽  
Molecular Nanostructures

We present electronic structure calculations based on a single-parameter plane wave expansion method for molecular nanostructures revealing excellent agreement with density functional theory and predicting metallic bands for chevron molecular dimers.

Theoretical investigation of energy gap bowing in CdSxSe1−x alloy quantum dots

2017 ◽  
Vol 19 (22) ◽  
pp. 14495-14502
Author(s):  
Laxman Tatikondewar ◽  
Anjali Kshirsagar
Keyword(s):  
Density Functional Theory ◽  
Quantum Dots ◽  
Electronic Structure ◽  
Theoretical Investigation ◽  
Density Functional ◽  
Energy Gap ◽  
Electronic Structure Calculations ◽  
Functional Theory ◽  
Alloy Quantum Dots ◽  
Structure Calculations

To investigate energy gap bowing in homogeneously alloyed CdSxSe1−x quantum dots (QDs) and to understand whether it is different from bulk, we perform density functional theory based electronic structure calculations for spherical QDs of different compositions x (0 ≤ x ≤ 1) and of varying sizes (2.2 to 4.6 nm).

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