scholarly journals Investigations on The Mechanism of Artificial Photosynthesis of Ca-Pc-PDI and Dendrimer Molecule by DFT Calculations

2018 ◽  
Vol 19 (2) ◽  
pp. 143
Author(s):  
Rahmat Gunawan ◽  
Ulinnuha Hammamiyah ◽  
Fahmi Fadillah ◽  
Chairul Saleh ◽  
Saibun Sitorus
Keyword(s):  
Energy Efficiency ◽  
Electron Transfer ◽  
Artificial Photosynthesis ◽  
Dft Method ◽  
Complex Compounds ◽  
Uv Spectrum ◽  
Functional Theory ◽  
Dendrimer Molecule ◽  
Homo And Lumo ◽  
Electron Transfers

Artificial photosynthesis modelling of Ca-Pc-PDI complex Ca Phthalocyanine Perylenediimide), and dendrimer molecule using Density of Functional Theory (DFT) Method has been studied to showed the energy efficiency of these compounds in terms of electron transfer in photosynthesis. The Analysis of Ca-Pc-PDI and dendrimer compound and also chlorophyl has been done in all computations using the GAMESS-US software. The computations result in this research showed that the large wavelength complex compounds of Ca-Pc-PDI obtained was 138.3299 nm and energy efficiency obtained was 0.89 eV. The data analysis states that the absorption of harvest light energy of complex compounds Ca-Pc-PDI lies in the far UV spectrum. The other side, the polyphenylene dendrimer structure molecular orbital analyses it was found that the dendrimer was capable of electron transfers as indicated by the existence of HOMO and LUMO and result comparisons with chlorophyll. UV wavelengths of the polyethylene dendrimer and chlorophyll, respectively, suggesting that the polyphenylene dendrimer is capable of substituting chlorophyll in artificial photosyntheses. We can states from the result that these compound ability to be applied in the modeling of artificial photosynthesis as a material of energy absorption that mimics the workings of chlorophyll in terms of electron transfer in natural photosynthesis process. Keywords: Artificial photosynthesis modelling, Ca-Phthalocyanine-Perylenediimide complex, and dendrimer molecule

Molecular Structure, Vibrational Spectroscopy and Homo, Lumo Studies of 4-methyl-N-(2-methylphenyl) Benzene Sulfonamide Using DFT Method

2013 ◽  
Vol 665 ◽  
pp. 101-111 ◽  
Author(s):  
K. Sarojini ◽  
H. Krishnan ◽  
Charles C. Kanagam ◽  
S. Muthu
Keyword(s):  
Density Functional ◽  
Molecular Electrostatic Potential ◽  
Structural Parameters ◽  
Dft Method ◽  
Basis Set ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Homo And Lumo ◽  
Homo Lumo ◽  
Sulfonamide Compound

The sulfonamide compound, 4-methyl-N-(2-methylphenyl) benzene sulfonamide has been synthesized and characterized by FTIR, NMR, UV-Vis, single crystal X-ray diffraction and thermal analysis. Density functional (DFT) calculations have been carried out for the title compound by performing DFT level of theory using B3LYP/6-31G (d,p) basis set. The calculated results show that the predicted geometry can well reproduce the structural parameters. Predicted vibrational frequencies have been assigned and compared with the experimental IR spectra and they support each other. In addition, atomic charges, frontier molecular orbitals and molecular electrostatic potential were carried out by using density functional theory (DFT/B3LYP) 6-31G (d, p) basis set. The calculated Homo and Lumo energies show that charge transfer occur in the molecule.

scholarly journals GEOMETRIC and ELECTRONIC PROPERTIES of OLIGOMERS BASED ON LUORINATED THIOPHENES and 1H-PHOSPHOLES: N- VERSUS P-TYPE MATERIALS

2010 ◽  
Vol 13 (2) ◽  
pp. 28-44
Author(s):  
Nguyen Tran Nguyen Pham ◽  
Quan Phung ◽  
Khung Moc ◽  
Thanh Tho Bui ◽  
Tho Minh Nguyen
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Dft Method ◽  
Excitation Energies ◽  
Geometrical Structures ◽  
Functional Theory ◽  
Homo And Lumo ◽  
Reorganization Energies ◽  
P Type ◽  
Geometric And Electronic Properties

A series of oligothiophenes and novel oligophospholes, consisting of fluorinated and perfluoroarene-substituted structures, were investigated by using density functional theory (DFT) method. The study focused on the geometrical structures and electronic properties. The degree of -conjugation in the neutral oligomers was studied by different approaches including analysis of predicted Raman spectra. The character of the charge carrier of the new substituted oligomers, either electron (n-type doping) or hole (p-type doping) transport, was predicted by comparing their properties, including the HOMO and LUMO energies, excitation energies, and reorganization energies, with those of their non-substituted parent oligomers. The DFT results are consistent with the available experimental data on the oligothiophenes for both geometries and conductivity properties. The results strongly suggest that an effective way of designing new materials with n-type conductivity is to introduce electron-withdrawing groups into the oligomer backbone. Interesting results were also obtained for oligomers based on 1H-phospholes, which are predicted to have interesting properties as new semiconductor materials..

Comparative Study of Stability and Detonation Characterization of AMF and ACF

2014 ◽  
Vol 997 ◽  
pp. 97-100
Author(s):  
Biao Yan ◽  
Hong Yu Zhou
Keyword(s):  
Density Functional ◽  
Dft Method ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Equivalent Equation ◽  
Molecular Reactivity ◽  
Homo And Lumo ◽  
Experimental Density ◽  
Density Results

3-Amino-4-aminoximidofurazan (AMF) and 3-Amino-4-cyanofurazan (ACF) are important precursor of synthesizing new furazanon (furoxano) energetic compounds. The density functional theory (DFT) method of the Amsterdam density functional (ADF) was used to calculate the geometry and frequency of AMF and ACF. The detonation velocity (D) and pressure (P) of the two compounds were estimated using the nitrogen equivalent equation according to the experimental density. Results showed that the initial decomposition step of AMF and ACF is the loss of NH2 from C2, N3 is the point of molecular reactivity of AMF and ACF, the changed in group have little effect on HOMO and LUMO. AMF has better thermal stability than ACF, but the detonation performance of ACF is finer than AMF.

Molecular Investigations of the Newly Synthesized Azomethines as Antioxidants: Theoretical and Experimental Studies

2019 ◽  
Vol 19 (6) ◽  
pp. 419-433 ◽  
Author(s):  
Siyamak Shahab ◽  
Masoome Sheikhi ◽  
Liudmila Filippovich ◽  
Evgenij Dikusar ◽  
Anhelina Pazniak ◽  
...  
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Experimental Studies ◽  
Antioxidant Property ◽  
Nbo Analysis ◽  
Antioxidant Potential ◽  
Functional Theory ◽  
Homo And Lumo ◽  
Intramolecular Hydrogen ◽  
Activity Mechanism

: In this study, the antioxidant property of new synthesized azomethins has been investigated as theoretical and experimental. Methods and Results: Density functional theory (DFT) was employed to investigate the Bond Dissociation Enthalpy (BDE), Mulliken Charges, NBO analysis, Ionization Potential (IP), Electron Affinities (EA), HOMO and LUMO energies, Hardness (η), Softness (S), Electronegativity (µ), Electrophilic Index (ω), Electron Donating Power (ω-), Electron Accepting Power (ω+) and Energy Gap (Eg) in order to deduce scavenging action of the two new synthesized azomethines (FD-1 and FD-2). Spin density calculations and NBO analysis were also carried out to understand the antioxidant activity mechanism. Comparison of BDE of FD-1 and FD-2 indicate the weal antioxidant potential of these structures. Conclusion: FD-1 and FD-2 have very high antioxidant potential due to the planarity and formation of intramolecular hydrogen bonds.

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)...

scholarly journals Boron-Decorated Pillared Graphene as the Basic Element for Supercapacitors: An Ab Initio Study

2021 ◽  
Vol 11 (8) ◽  
pp. 3496
Author(s):  
Dmitry A. Kolosov ◽  
Olga E. Glukhova
Keyword(s):  
Density Functional ◽  
Dft Method ◽  
Heat Of Formation ◽  
Basic Element ◽  
Supercapacitor Electrode ◽  
Functional Theory ◽  
Icosahedral Clusters ◽  
New Material ◽  
Principle Density Functional Theory ◽  
Specific Quantum

In this work, using the first-principle density functional theory (DFT) method, we study the properties of a new material based on pillared graphene and the icosahedral clusters of boron B12 as a supercapacitor electrode material. The new composite material demonstrates a high specific quantum capacitance, specific charge density, and a negative value of heat of formation, which indicates its efficiency. It is shown that the density of electronic states increases during the addition of clusters, which predictably leads to an increase in the electrode conductivity. We predict that the use of a composite based on pillared graphene and boron will increase the efficiency of existing supercapacitors.

scholarly journals Spectroscopic evidence for direct flavin-flavin contact in a bifurcating electron transfer flavoprotein

2020 ◽  
Vol 295 (36) ◽  
pp. 12618-12634
Author(s):  
H. Diessel Duan ◽  
Nishya Mohamed-Raseek ◽  
Anne-Frances Miller
Keyword(s):  
Electron Transfer ◽  
Density Functional ◽  
Protein Denaturation ◽  
Rhodopseudomonas Palustris ◽  
Density Functional Theory Calculations ◽  
Site Directed Mutagenesis ◽  
Functional Theory ◽  
Electron Transfer Flavoprotein ◽  
Midpoint Potential ◽  
Ct Complex

A remarkable charge transfer (CT) band is described in the bifurcating electron transfer flavoprotein (Bf-ETF) from Rhodopseudomonas palustris (RpaETF). RpaETF contains two FADs that play contrasting roles in electron bifurcation. The Bf-FAD accepts electrons pairwise from NADH, directs one to a lower-reduction midpoint potential (E°) carrier, and the other to the higher-E° electron transfer FAD (ET-FAD). Previous work noted that a CT band at 726 nm formed when ET-FAD was reduced and Bf-FAD was oxidized, suggesting that both flavins participate. However, existing crystal structures place them too far apart to interact directly. We present biochemical experiments addressing this conundrum and elucidating the nature of this CT species. We observed that RpaETF missing either FAD lacked the 726 nm band. Site-directed mutagenesis near either FAD produced altered yields of the CT species, supporting involvement of both flavins. The residue substitutions did not alter the absorption maximum of the signal, ruling out contributions from residue orbitals. Instead, we propose that the residue identities modulate the population of a protein conformation that brings the ET-flavin and Bf-flavin into direct contact, explaining the 726 nm band based on a CT complex of reduced ET-FAD and oxidized Bf-FAD. This is corroborated by persistence of the 726 nm species during gentle protein denaturation and simple density functional theory calculations of flavin dimers. Although such a CT complex has been demonstrated for free flavins, this is the first observation of such, to our knowledge, in an enzyme. Thus, Bf-ETFs may optimize electron transfer efficiency by enabling direct flavin-flavin contact.

Excited states of analogue models of M-bacteriochlorophylls (M = Mg, Zn) in the photosynthetic reaction center: a time-dependent density functional theory study

2002 ◽  
Vol 06 (10) ◽  
pp. 617-625 ◽  
Author(s):  
Yoichi Yamaguchi
Keyword(s):  
Electron Transfer ◽  
Excited States ◽  
Density Functional ◽  
Photosynthetic Reaction Center ◽  
Excited Electron ◽  
Time Dependent ◽  
Analogue Model ◽  
Functional Theory ◽  
Special Pair ◽  
Dependent Density

Using time-dependent density functional theory (TDDFT), the excited states of the analogue model Mg -bacteriochlorophyll b - imidazole ( BChl -Im) dimer (P) for a special pair in the photosynthetic reaction center (RC) of Rhodopseudomonas (Rps.) viridis were examined. The calculated low-lying excited states and optimal geometries are in good agreement with experimental data. The order of the lowest unoccupied molecular orbital (LUMO) energies of P, the monomeric "accessory" BChl -Im (B), and bacteriopheophytin b ( H ) indicates the possibility of the light-induced electron transfer from P to H via B. The Im ligand of B destabilizes Goutermann's four-orbitals of BChl by 0.3-0.4 eV. With no energetic difference in the LUMOs between H and BChl , the Im ligands of P and B play an important role in providing a greater energetic gradient to the LUMOs along with the pathway for the excited-electron transfer in RC, resulting in the reduced reverse electron transfer from H to P (via B). Thus it is expected that the asymmetric Mg -Im interactions will directly affect the pathway of the excited-electron transfer. Using the deformed heterodimer (P') formed by the BChl halves with and without Im as the primary donor model, its cation radical P'+ was calculated as to whether the experimental asymmetric spin-density distribution can reproduce. The excited states of the analogue model Zn - BChl -Im dimer for a special pair in RC of the recently discovered Acidiphilium rubrum were also examined for a comparison with P.

First principles analysis of oxygen vacancy formation and migration in Sr2BMoO6 (B = Mg, Co, Ni)

RSC Advances ◽  
2016 ◽  
Vol 6 (38) ◽  
pp. 31968-31975 ◽  
Author(s):  
Shuai Zhao ◽  
Liguo Gao ◽  
Chunfeng Lan ◽  
Shyam S. Pandey ◽  
Shuzi Hayase ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Oxygen Vacancy ◽  
First Principles ◽  
Density Functional ◽  
Dft Method ◽  
Double Perovskites ◽  
Functional Theory ◽  
Oxygen Vacancy Formation ◽  
The Density Functional Theory ◽  
And Migration

In this work, we present a detailed first-principles investigation on the stoichiometric and oxygen-deficient structures of double perovskites, Sr2BMoO6 (B = Mg, Co and Ni), using the density functional theory (DFT) method.

Sign in / Sign up

Export Citation Format

Share Document