scholarly journals Molecular, Electronic, Nonlinear Optical and Spectroscopic Analysis of Heterocyclic 3-Substituted-4-(3-methyl-2-thienylmethyleneamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones: Experiment and DFT Calculations

2021 ◽  
Vol 27 (1) ◽  
pp. 1-16
Author(s):  
Murat Beytur ◽  
Ihsan Avinca
Keyword(s):  
Nonlinear Optical ◽  
Chemical Potential ◽  
Energy Gap ◽  
Basis Set ◽  
Molecular Vibration ◽  
Excitation Energies ◽  
Visible Absorption ◽  
Td Dft ◽  
Uv Visible ◽  
Experimental Values

Abstract In the present study, 3-p-methoxybenzyl/m-chlorobenzyl/phenyl-4-(3-methyl-2-thienylmethyleneamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones were obtained from the reaction between 3-methylthiophene-2-carbaldehyde and three different 4-amino-(3-p-methoxybenzyl/m-chlorobenzyl/phenyl)-4,5-dihydro-1H-1,2,4-triazole-5-ones. In order to compare experimental and theoretical values, the geometric parameter, electronic, nonlinear optical properties, molecular electrostatic potentials and spectroscopic properties of 3-substituted-4-(3-methyl-2-thienylmethyleneamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones have been simulated. The electronic properties of the newly synthesized compounds were calculated using DFT/B3LYP and DFT/B3PW91 methods revealing parameters such as ionization potential, electron affinity, energy gap, electronegativity, molecular hardness, molecular softness, electrophilic index, nucleophilic index and chemical potential, all obtained from HOMO and LUMO energies, dipole moments and total energies. UV-visible absorption spectra and the stimulation contributions in UV-visible transitions were obtained by using TD-DFT/B3LYP/6-311G(d,p) and TD-DFT/B3PW91/6-311G(d,p) methods in ethanol. The calculated absorption wavelengths, oscillator power and excitation energies were compared with experimental values. In line with DFT, the numbers of molecular vibration were analyzed through the basis set of 6-311G(d,p). The recording of FT-IR frequencies was done for the pertinent compound. The recorded frequencies through DFT/B3LYP and DFT/B3PW91 methods were compared to experimental values, with a result gained closest to the values of B3LYP. Finally, the Gaussian09W program package in DMSO phase, starting from the optimized structure, has been instrumental in calculating the 13C-NMR and 1H-NMR chemical shift values of the GIAO method.

scholarly journals FT-IR, FT-Raman, Homo-Lumo and UV-Visible Spectral Analysis of E-(N′-(1H-INDOL-3YL) Methylene Isonicotinohydrazide)

2017 ◽  
Vol 1 (3) ◽  
pp. 1-37
Author(s):  
D. Sumathi ◽  
H. Saleem ◽  
A. Nathiya ◽  
N. RameshBabu ◽  
D. Usha
Keyword(s):  
Energy Gap ◽  
Solid Phase ◽  
Basis Set ◽  
Excitation Energies ◽  
B3lyp Method ◽  
Td Dft ◽  
Ft Ir ◽  
Experimental Values ◽  
Homo Lumo ◽  
Ft Raman

A combined experimental and theoretical study on molecular and vibrational structure of E-N¢ (ICINH) had been carried out. The FTIR, FT-Raman and UV-Vis spectra of ICINH were recorded in the solid phase. The optimized geometry was calculated by B3LYP method with 6-311++G(d,p) level of basis set. The harmonic vibrational frequencies, IR intensities and Raman scattering activities of the title compound were calculated at same level of theory. The scaled theoretical wavenumber showed very good agreement with the experimental values. The mulliken charges and thermodynamic functions of the ICINH were also performed at same level of theory. NLO and a study on the electronic properties such as excitation energies and wavelength, were performed by TD-DFT approach. HOMO–LUMO energy gap was also calculated and interpreted.

scholarly journals Molecular modelling, spectroscopic characterization and nonlinear optical analysis on N-Acetyl-DL-methionine

2020 ◽  
Vol 66 (6 Nov-Dec) ◽  
pp. 749
Author(s):  
N. Günay ◽  
Ö. Tamer ◽  
D. Avcı ◽  
E. Tarcan ◽  
Y. Atalay
Keyword(s):  
Electronic Properties ◽  
Title Compound ◽  
Density Functional ◽  
Nonlinear Optical ◽  
Energy Gap ◽  
Spectroscopic Characterization ◽  
Oscillator Strengths ◽  
Basis Set ◽  
Molecular Electrostatic Potential Surface ◽  
Experimental Values

In this present methodical study, on the basis of the density functional theory (DFT), the first-principles calculations have been employed successfully to study the structural and electronic properties of N-acetyl-DL-methionine (C7H13NO3S) which is a derivative of DL-methionine which is also known DL-2-amino-4-methyl-thiobutanoic acid. Optimized molecular structure, vibrational frequencies and also 13C and 1H NMR chemical shift values of the title compound are provided in a detailed manner by using B3LYP and HSEH1PBE functionals by applying 6-311++G(d,p) basis set for calculations using Gaussian 09W program. The comparison of the calculated values with the experimental values provides important information about the title compound. In addition, the electronic properties (UV-Vis calculations) of the title compound, such as HOMO-LUMO energy values and energy gap, absorption wavelengths, oscillator strengths were performed basing on the optimized structure in gas phase. Moreover, the molecular electrostatic potential surface, dipole moment, nonlinear optical properties, linear polarizabilities and first hyperpolarizabilities and chemical parameters have also been studied.

scholarly journals Predictive calculation of structural, nonlinear optical, electronic and thermodynamic properties of andirobin molecule from ab initio and DFT methods

2021 ◽  
Vol 3 (9) ◽  
Author(s):  
M. T. Ottou Abe ◽  
C. L. Nzia ◽  
L. Sidjui Sidjui ◽  
R. A. Yossa Kamsi ◽  
C. D. D. Mveme ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Density Functional ◽  
Nonlinear Optical ◽  
Energy Gap ◽  
Basis Set ◽  
Dft Methods ◽  
Functional Theory ◽  
Hartree Fock ◽  
H Nmr ◽  
Experimental Values

AbstractThe structural, nonlinear optical, electronic and thermodynamic properties of andirobin molecule were carried out by density functional theory at the B3LYP, WB97XD level and at the Restricted Hartree–Fock level by employing 6–311G(d,p) basis set. The obtained values of bond lengths, bond angles, 1H NMR and 13C NMR are in good agreement with experimental values. The dipole moment and first static hyperpolarizability show that andirobin can be applied in nonlinear optical devices. HOMO–LUMO energy gap values were found to be greater than 4 eV and lead us to the conclusion that this molecule can be used as insulator in many electronic devices. The thermal energy (E), molar heat capacity at constant volume $$(C_{v}$$ ( C v ) and entropy (S) were also calculated.

scholarly journals A Theoretical Study of 5-methyl-2-isopropylphenol (Thymol) by DFT

2021 ◽  
pp. 812-830
Author(s):  
Raksha Gupta
Keyword(s):  
Population Analysis ◽  
Dft Method ◽  
Geometric Optimization ◽  
Oscillator Strengths ◽  
Basis Set ◽  
Excitation Energies ◽  
Mulliken Population ◽  
Visible Absorption ◽  
Vertical Excitation ◽  
Td Dft

Gaussian 09, RevisionA.01, software package was used for the theoretical quantum chemical calculations of 5-methyl-2-isopropylphenol. DFT/B3LYP/6-311G (d, p) basis was used to perform geometric optimization and vibrational frequency determination of the molecule. The statistical thermochemical calculations of the molecule were done at DFT/B3LYP/6-311G (d, p) basis set to calculate the standard thermodynamic functions: heat capacity (CV), entropy (S) and Enthalpy (E). Various NLO properties like total dipole moment (µ), mean linear polarizability (α), anisotropic polarizability (Δα), first order polarizability (β), and second order hyperpolarizability (γ) in terms of x, y, z components were calculated at DFT/B3LYP/6-311G (d, p) basis set for 5-methyl-2-isopropylphenol. Mulliken population analysis was also done using the same basis set. Time Dependent DFT (TD-DFT) method using the same basis set was used to compute UV-Visible absorption spectra, ECD spectra, electronic transitions, vertical excitation energies and oscillator strengths of 5-methyl-2-isopropylphenol.FMO analysis, ESP study were also done using the same basis set.

scholarly journals Characterization and Theoretical study of Nonlinear Optical Properties of (2E)-1-(2, 4-dichlorophenyl)-3-(4-methylphenyl) prop-2-en-1-one

2021 ◽  
Vol 9 (11) ◽  
pp. 1657-1667
Author(s):  
Virupakshi M Bhumannavar
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Nonlinear Optical ◽  
Theoretical Study ◽  
Basis Set ◽  
Optical Parameters ◽  
Optical Study ◽  
Functional Theory ◽  
Td Dft ◽  
Uv Visible

Abstract: The structural confirmation of the title compound is done by theoretical and experimental study. Experimental techniques such as FTIR, proton NMR, UV-Visible, thermal analysis (TGA & DTA) are employed. Density functional theory is used to analyze spectroscopic data scrutinized. Second order nonlinear optical parameters are obtained. The experimental results are analyzed with theoretically obtained data from density functional theory. TD-DFT also employed for the MLDCLC at different basis set. Keywords: DFT Study, nonlinear optical study, FTIR, 1H NMR

Theoretical investigation on tautomerism and NLO properties of Salicylideneaniline derivatives

2021 ◽  
Author(s):  
N. Daho ◽  
N. Benhalima ◽  
F. KHELFAOUI ◽  
O. SADOUKI ◽  
M. Elkeurti ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Intramolecular Proton Transfer ◽  
Basis Set ◽  
Frontier Molecular Orbital ◽  
Molecular Orbital Calculations ◽  
Visible Absorption ◽  
Charge Delocalization ◽  
Intramolecular Hydrogen

In this work, a comprehensive investigation of the salicylideneaniline derivatives is carried out using density functional theory to determine their linear and non-linear optical properties. Geometry optimizations, for gas and solvent phases, of the tautomers (enol and keto forms) are calculated using B3LYP levels with 6–31G (d,p) basis set . An intramolecular proton transfer, for 1SA-E and 2SA-E, is performed by a PES scan process at the B3LYP/6-31G (d,p) level. The optical properties are determined and show that they have extremely high nonlinear optical properties. In addition, the RDG analysis, MEP, and gap energy are calculated. The low energy gap value indicates the possibility of intramolecular charge transfer. The frontier molecular orbital calculations clearly show the inverse relationship of HOMO–LUMO gap with the first-order hyperpolarizability (β = 59.6471 × 10-30 esu), confirming that the salicylideneaniline derivatives can be used as attractive future NLO materials. Therefore, the reactive sites are predicted using MEP and the visible absorption maxima are analyzed using a theoretical UV–Vis spectrum. Natural bond orbitals are used to investigate the stability, charge delocalization, and intramolecular hydrogen bond.

FIRST-PRINCIPLES STUDY OF THE ELECTRONIC, LINEAR, AND NONLINEAR OPTICAL PROPERTIES OF Li(Nb, Ta)O3

2010 ◽  
Vol 24 (32) ◽  
pp. 6277-6290 ◽  
Author(s):  
SULEYMAN CABUK
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Nonlinear Optical ◽  
Energy Gap ◽  
Local Density ◽  
Theoretical Calculations ◽  
Total Density ◽  
Functional Theory ◽  
Experimental Values ◽  
Electron Energy Loss

We investigate the energy band structure, total density of states, the linear, nonlinear optical (NLO) response, and the electron energy-loss spectrum for Li(Nb, Ta)O 3 using first principles calculations based on density functional theory in its local density approximation. Our calculation shows that these compounds have similar structures. The indirect band gaps of 3.39 eV (LiNbO3) and 3.84 eV (LiTaO3) at the Γ–Z direction in the Brillouin zone are found. A simple scissor approximation is applied to adjust the band energy gap from the calculations to match the experimental values. The optical spectra are analyzed and the origins of some of the peaks in the spectra are discussed in terms of calculated electronic structure. Calculations are reported for the frequency-dependent complex second-order NLO susceptibilities [Formula: see text] up to 10 eV and for zero-frequency limit [Formula: see text]. The results are compared with the theoretical calculations and the available experimental data.

scholarly journals The Influence of Polarization on the Spectral Density

2019 ◽  
Author(s):  
Tim Zuehlsdorff ◽  
Hanbo Hong ◽  
Liang Shi ◽  
Christine Isborn
Keyword(s):  
Spectral Density ◽  
Condensed Phase ◽  
Degrees Of Freedom ◽  
Nonlinear Optical ◽  
Energy Gap ◽  
Protein Complexes ◽  
Computational Cost ◽  
Spectral Densities ◽  
Excitation Energies ◽  
Vibrational Coupling

<p>Accurate spectral densities are necessary for computing realistic exciton dynamics and nonlinear optical spectra of chromophores in condensed phase environments, including multi-chromophore pigment-protein systems. However, due to the significant computational cost of computing spectral densities from first principles, requiring many thousands of excited state calculations, most simulations of realistic systems rely on treating the environment as fixed point charges. Here, using a number of representative systems ranging from solvated chromophores to the photoactive yellow protein (PYP), we demonstrate that the quantum mechanical (QM) polarization of the environment is key to obtaining accurate spectral densities and lineshapes within the cumulant framework. We show that the QM environment can enhance or depress the coupling of fast chromophore degrees of freedom to the energy gap, altering the electronic-vibrational coupling and the resulting vibronic progressions in the absorption spectrum. In analyzing the physical origin of peaks in the spectral density, we identify vibrational modes that couple the electron and the hole as being particularly sensitive to the QM screening of the environment. For PYP, we reveal the need for a careful determination of the appropriate QM region to obtain reliable spectral densities. Our results indicate that the QM polarization of the environment can be crucial not just for excitation energies, but also for electronic-vibrational coupling in complex systems, with implications for the correct modeling of linear and nonlinear optical spectroscopy in the condensed phase, as well as energy transfer in pigment-protein complexes.<br></p>

scholarly journals The Influence of Polarization on the Spectral Density

2019 ◽  
Author(s):  
Tim Zuehlsdorff ◽  
Hanbo Hong ◽  
Liang Shi ◽  
Christine Isborn
Keyword(s):  
Spectral Density ◽  
Condensed Phase ◽  
Degrees Of Freedom ◽  
Nonlinear Optical ◽  
Energy Gap ◽  
Protein Complexes ◽  
Computational Cost ◽  
Spectral Densities ◽  
Excitation Energies ◽  
Vibrational Coupling

<p>Accurate spectral densities are necessary for computing realistic exciton dynamics and nonlinear optical spectra of chromophores in condensed phase environments, including multi-chromophore pigment-protein systems. However, due to the significant computational cost of computing spectral densities from first principles, requiring many thousands of excited state calculations, most simulations of realistic systems rely on treating the environment as fixed point charges. Here, using a number of representative systems ranging from solvated chromophores to the photoactive yellow protein (PYP), we demonstrate that the quantum mechanical (QM) polarization of the environment is key to obtaining accurate spectral densities and lineshapes within the cumulant framework. We show that the QM environment can enhance or depress the coupling of fast chromophore degrees of freedom to the energy gap, altering the electronic-vibrational coupling and the resulting vibronic progressions in the absorption spectrum. In analyzing the physical origin of peaks in the spectral density, we identify vibrational modes that couple the electron and the hole as being particularly sensitive to the QM screening of the environment. For PYP, we reveal the need for a careful determination of the appropriate QM region to obtain reliable spectral densities. Our results indicate that the QM polarization of the environment can be crucial not just for excitation energies, but also for electronic-vibrational coupling in complex systems, with implications for the correct modeling of linear and nonlinear optical spectroscopy in the condensed phase, as well as energy transfer in pigment-protein complexes.<br></p>

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