scholarly journals Molecular Structure, Homo-Lumo and Vibrational Analysis Of Ergoline By Density Functional Theory

2021 ◽  
Vol 14 (14) ◽  
pp. 21-30
Author(s):  
Bhawani Datt Joshi ◽  
Ghanshyam Thakur ◽  
Manoj Kumar Chaudhary
Keyword(s):  
Density Functional Theory ◽  
Quantum Chemical ◽  
Density Functional ◽  
Graphical Representation ◽  
Energy Gap ◽  
Quantum Chemical Study ◽  
Vibrational Analysis ◽  
Basis Set ◽  
Potential Energy Distribution ◽  
Functional Theory

In this work, quantum chemical study on a natural product ergoline has been presented using density functional theory (DFT) employing 6-311++G(d,p) basis set. A complete vibrational assignment has been performed for the theoretical FT-IR and Raman wavenumbers along with the potential energy distribution (PED) with the result of quantum chemical calculations. The structure–activity relationship has been interpreted by mapping electrostatic potential surface (MEP). Graphical representation of frontier molecular orbitals with their energy gap have been analyzed theoretically for both the gaseous and solvent environment employing time dependent density functional theory (TDDFT) employing 6-31G basis set.

SOLVENT EFFECTS ON THE ELECTRONIC STRUCTURE AND NON-LINEAR OPTICAL PROPERTIES OF PYRENE AND SOME OF ITS DERIVATIVES BASED ON DENSITY FUNCTIONAL THEORY

2021 ◽  
Vol 4 (4) ◽  
pp. 236-251
Author(s):  
A. S. Gidado ◽  
L. S. Taura ◽  
A. Musa
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Energy Gap ◽  
Chemical Reactivity ◽  
Basis Set ◽  
Lumo Energy ◽  
Functional Theory ◽  
Organic Optoelectronic ◽  
Homo Lumo

Pyrene (C16H10) is an organic semiconductor which has wide applications in the field of organic electronics suitable for the development of organic light emitting diodes (OLED) and organic photovoltaic cells (OPV). In this work, Density Functional Theory (DFT) using Becke’s three and Lee Yang Parr (B3LYP) functional with basis set 6-311++G(d, p) implemented in Gaussian 03 package was  used to compute total energy, bond parameters, HOMO-LUMO energy gap, electron affinity, ionization potential, chemical reactivity descriptors, dipole moment, isotropic polarizability (α), anisotropy of polarizability ( Δ∝) total first order hyper-polarizability () and second order hyperpolarizability (). The molecules used are pyrene, 1-chloropyrene and 4-chloropyrene  in gas phase and in five different solvents: benzene, chloroform, acetone, DMSO and water. The results obtained show that solvents and chlorination actually influenced the properties of the molecules. The isolated pyrene in acetone has the largest value of HOMO-LUMO energy gap of and is a bit closer to a previously reported experimental value of  and hence is the most stable. Thus, the pyrene molecule has more kinetic stability and can be described as low reactive molecule. The calculated dipole moments are in the order of 4-chloropyrene (1.7645 D) < 1-chloropyrene (1.9663 D) in gas phase. The anisotropy of polarizability ( for pyrene and its derivatives were found to increase with increasing polarity of the solvents.  In a nutshell, the molecules will be promising for organic optoelectronic devices based on their computed properties as reported by this work.

scholarly journals Theoretical Study of a Class of Organic D-π-A Dyes for Polymer Solar Cells: Influence of Various π-Spacers

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 163
Author(s):  
Nguyen Van Trang ◽  
Tran Ngoc Dung ◽  
Ngo Tuan Cuong ◽  
Le Thi Hong Hai ◽  
Daniel Escudero ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Solar Cells ◽  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Polymer Solar Cells ◽  
Basis Set ◽  
Structure Theory ◽  
Functional Theory ◽  
Alkyl Groups

A class of D-π-A compounds that can be used as dyes for applications in polymer solar cells has theoretically been designed and studied, on the basis of the dyes recently shown by experiment to have the highest power conversion efficiency (PCE), namely the poly[4,8-bis(5-(2-butylhexylthio)thiophen-2-yl)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-TZNT] (PBDTS-TZNT) and poly[4,8-bis(4-fluoro-5-(2-butylhexylthio)thiophen-2-yl)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-TZNT] (PBDTSF-TZNT) substances. Electronic structure theory computations were carried out with density functional theory and time-dependent density functional theory methods in conjunction with the 6−311G (d, p) basis set. The PBDTS donor and the TZNT (naphtho[1,2-c:5,6-c]bis(2-octyl-[1,2,3]triazole)) acceptor components were established from the original substances upon replacement of long alkyl groups within the thiophene and azole rings with methyl groups. In particular, the effects of several π-spacers were investigated. The calculated results confirmed that dithieno[3,2-b:2′,3′-d] silole (DTS) acts as an excellent π-linker, even better than the thiophene bridge in the original substances in terms of well-known criteria. Indeed, a PBDTS-DTS-TZNT combination forms a D-π-A substance that has a flatter structure, more rigidity in going from the neutral to the cationic form, and a better conjugation than the original compounds. The highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gap of such a D-π-A substance becomes smaller and its absorption spectrum is more intense and red-shifted, which enhances the intramolecular charge transfer and makes it a promising candidate to attain higher PCEs.

Electronic Structure, Nonlinear Optical Properties, and Vibrational Analysis of Ethyl benzoate by Density Functional Theory

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Tanveer Hasan ◽  
P. K. Singh
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Vibrational Analysis ◽  
Ethyl Benzoate ◽  
Computational Method ◽  
Basis Set ◽  
Vibrational Modes ◽  
Normal Coordinate ◽  
Functional Theory ◽  
Vibrational Bands

This work deals with the vibrational spectroscopy of Ethyl benzoate (C9H10O2). The fundamental vibrational frequencies and intensity of vibrational bands were evaluated using density functional theory (DFT) using standard HF/6-31G(d,p) and B3LYP/6-31G(d,p) methods and basis set combinations. The vibrational spectra were interpreted, with the aid of normal coordinate analysis based on a scaled quantum mechanical force field. The infrared and Raman spectra were also predicted from the calculated intensities. Comparison of simulated spectra with the experimental spectra provides important information about the ability of the computational method to describe the vibrational modes.

scholarly journals Electronic structures and photovoltaic properties of a novel phthalocyanine and titanium dioxide phthalocyanine for dye sensitized-solar cells

2021 ◽  
Vol 6 (3) ◽  
pp. 107-115
Author(s):  
Fares A. Yasseen ◽  
Faeq A. Al-Temimei
Keyword(s):  
Density Functional Theory ◽  
Solar Cells ◽  
Electronic Structures ◽  
Density Functional ◽  
Energy Gap ◽  
Dye Sensitized Solar Cells ◽  
Solar Spectrum ◽  
Electron Injection ◽  
Basis Set ◽  
Functional Theory

In the present work, geometries, electronic structures, photovoltaic and optical properties have been carried out on a series of structures formation of phthalocyanine and Titanylphthalocyanine dyes, which are replaced by several subgroup. A density functional theory (DFT) approach together with hybrid function (B3LYP) at SDD basis set was used for the ground state properties in the gas phase. The time-dependent density functional theory (TD-DFT)/ B3LYP was used to investigate the excitation properties of new dyes and analyzed the trends in their optical and redox characteristics. Theoretical principles of HOMO and LUMO energy levels of dyes is requisite in analyzing organic solar cells, thus, HOMO, LUMO levels, open circuit voltage, energy gap, light harvestings efficiency, electron regeneration and electron injection have been calculated and discussed. The outcome of the efficiency, the considered dyes explain absorption energy and wavelength properties that correspond to the solar spectrum requirements. According to results, all the considered materials have a good property and possibility of electron injection procedure from the dyes to conduction band of TiO2, PC60BM or PC60BM. As a result, the molecular changes affect the electronic properties of dye molecules for solar cells. Also, a study of new dyes sensitizers showed that designed materials will be excellent sensitizers. Theoretical designing will prae a way for experimentalists to synthesize the efficient sensitizers for solar cells clearer.

scholarly journals Reliable and computationally affordable prediction of the energy gap of (TiO2)n (10 ≤ n ≤ 563) nanoparticles from density functional theory

2018 ◽  
Vol 20 (28) ◽  
pp. 18907-18911 ◽  
Author(s):  
Ángel Morales-García ◽  
Rosendo Valero ◽  
Francesc Illas
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Energy Gap ◽  
Basis Set ◽  
Functional Theory ◽  
Orbital Basis

Suitable and practical way to estimate Ogap of TiO2 nanoparticles containing up to thousands of atoms from computationally affordable relativistic all-electron calculations with a numerical atomic centered orbital basis set.

scholarly journals Structure, Electronic And Vibrational Study of 7-Methyl-2,3-Dihydro-(1,3)Thiazolo(3,2-A) Pyrimidin-5-One by Using Density Functional Theory

2018 ◽  
Vol 22 (2) ◽  
pp. 1-11
Author(s):  
Bhawani Datt Joshi ◽  
Janga Bahadur Khadka ◽  
Atamram Bhatt
Keyword(s):  
Density Functional Theory ◽  
Molecular Orbital ◽  
Density Functional ◽  
Basis Set ◽  
Orbital Energy ◽  
Potential Energy Distribution ◽  
Functional Theory ◽  
Hartree Fock ◽  
Solvent Phase ◽  
Lowest Unoccupied Molecular Orbital

 We have presented molecular structure and vibrational wavenumber assignments of 7-methyl-2,3-dihydro-(1,3)thiazolo(3,2-a)pyrimidin-5-one. Both ab initio Hartree-Fock and density functional theory employing 6-311++G(d,p) basis set have been used for the calculations. The scaled values of the calculated vibrational frequencies were used for assignments on the basis of potential energy distribution. The structure-activity relation has been interpreted by mapping molecular electrostatic potential surface. Electronic properties have been analyzed by using time dependent density functional theory (TD-DFT) for both gaseous and solvent phase. The calculated HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy values show that the charge transfer occurs within the molecule. Journal of Institute of Science and TechnologyVolume 22, Issue 2, January 2018, Page: 1-11 

Conformational and Vibrational Analysis of 2,4-, 2,5- and 2,6-Difluorobenzaldehydes by ab initio Hartree-Fock and Density Functional Theory Calculations

2008 ◽  
Vol 63 (3-4) ◽  
pp. 175-182 ◽  
Author(s):  
Adnan Sağlam ◽  
Fatih Ucun
Keyword(s):  
Density Functional Theory ◽  
Ab Initio ◽  
Density Functional ◽  
Vibrational Analysis ◽  
Molecular Structures ◽  
Basis Set ◽  
Functional Theory ◽  
Vibrational Assignments ◽  
Hartree Fock ◽  
The Mean

The optimized molecular structures, vibrational frequencies and corresponding vibrational assignments of the two planar O-cis and O-trans rotomers of 2,4-, 2,5- and 2,6-difluorobenzaldehyde have been calculated using ab initio Hartree-Fock (HF) and density functional theory (B3LYP) methods with the 6-311++G(d,p) basis set level. The calculations were adapted to the CS symmetries of all the molecules. The O-trans rotomers with lower energy of all the compounds have been found as preferential rotomers in the ground state. The mean vibrational deviations between the vibrational frequency values of the two conformers of all the compounds have been shown to increase while the relative energies increase, and so it has been concluded that the higher the relative energy between the two conformers the bigger is the mean vibrational deviation.

scholarly journals Density functional theory study of molecular structure, Electronic properties, UV–Vis spectra on coumarin102.

2016 ◽  
Vol 13 (2) ◽  
pp. 143-152
Author(s):  
Baghdad Science Journal
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Chemical Potential ◽  
Energy Gap ◽  
Spectral Characteristics ◽  
Functional Model ◽  
Electronic States ◽  
Basis Set ◽  
Uv Spectrum ◽  
Functional Theory

The various properties of the ground and excited electronic states of coumarins 102 using density functional theory (DFT) and time-dependent density functional theory (TDDFT) was calculated by the B3LYP density functional model with 6-31G(d,p) basis set by Gaussian 09 W program. Spectral characteristics of coumarin102 have been probed into by methods of experimental UV-visible, and quantum chemistry. The UV spectrum was measured in methanol. The optimized structures, total energies, electronic states (HOMO- LUMO), energy gap, ionization potentials, electron affinities, chemical potential, global hardness, softness, global electrophilictity, and dipole moment were measured. We find good agreement between experimental data of UV spectrum and TDDFT excitationenergies.

scholarly journals SPECTRAL CHARACTERISTICS OF CONFORMATION ISOMERS OF MESO-OCTAMETHYL-CALIX(4)PYRROLE BASED ON QUANTUM-CHEMICAL CALCULATIONS

2018 ◽  
Vol 59 (5) ◽  
pp. 30
Author(s):  
Oleg V. Surov ◽  
Mikhail A. Krestianinov ◽  
Nugzar Zh. Mamardashvili
Keyword(s):  
Density Functional Theory ◽  
Electronic Absorption ◽  
Quantum Chemical ◽  
Density Functional ◽  
Dynamic Equilibrium ◽  
Electronic Absorption Spectra ◽  
Spectral Characteristics ◽  
Structure Optimization ◽  
Basis Set ◽  
Functional Theory

The structure optimization and calculation of electronic absorption spectra of meso-octa-methylcalix(4)pyrrole conformers was performed  by density- functional theory using hybrid B3LYP functional in cc-pVTZ basis set of Gaussian 09 package. Analysis of experimental UV-Vis spectra of solutions of calix(4)pyrrole was carried out in various solvents. The conclusion on the existence of a dynamic equilibrium between conformers in solutions of meso-octamethylcalix(4)pyrrole was made.

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