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Öğe A study on optimum transition state and tautomeric structures of a bis-heterocyclic monoazo dye(Indian Assoc Cultivation Science, 2015) Karakaya, M.; Yildiz, M.In this study, possible tautomeric forms and ground state conformers of a bis-heterocyclic monoazo dye, 4-[ethyl 4'-methyl-5'-(phenylcarbamoyl) thiophene-3'-carboxylate-2'-ylazo]-3-methyl-1H-pyrazolin-5-one, have been calculated using density functional theory methods with 6-31G (d) basis set. H-1 and C-13 chemical shifts of tautomeric forms have been calculated. Calculated vibrational frequencies and chemical shifts have been compared with corresponding experimental data. Using time-dependent Hartree-Fock method, electronic absorption spectrum of title compound has been calculated and compared with experimental maximum wavelength data. Quantum Synchronous Transit2 approaches have been used for finding the optimum transition state and tautomeric forms of studied molecule. Calculations have shown that the most probable preferential form of this molecule in ground state is hydrazo-keto form. The calculations of frontier molecular orbitals and first order hyperpolarizability have also confirmed this stability.Öğe A theoretical study on tautomeric structures of 4'-nitroazobenzene-2,4-diol and 4-methyl-4'-nitroazobenzene-2,6-diol compounds(Maik Nauka/Interperiodica/Springer, 2014) Karakaya, M.; Ucun, F.The goal of this study is to determine the most stable tautomeric forms, and their ground state conformers of 4'-nitroazobenzene-2,4-diol and 4-methyl-4'-nitroazobenzene-2,6-diol compounds. The calculations have shown that the most stable tautomeric forms of the compounds are hydrazo form for 4'-nitroazobenzene-2,4-diol and azo form for 4-methyl-4'-nitroazobenzene-2,6-diol. Besides, the vibrational frequencies, H-1 and C-13 NMR shifts, frontier molecular orbital's energies for the tautomeric forms of the compounds calculated by using density functional theory-B3LYP method with 6-311G(d) basis set were interpreted. All the assignments of the theoretical frequencies were identified by potential energy distribution (PED) analysis. Generally, theoretical spectral results were seen to be in a good agreement with the corresponding experimental data.Öğe Ab-initio and DFT methodologies for computing hyperpolarizabilities and susceptibilities of highly conjugated organic compounds for nonlinear optical applications(Elsevier, 2016) Karakas, A.; Karakaya, M.; Ceylan, Y.; El Kouari, Y.; Taboukhat, S.; Boughaleb, Y.; Sofiani, Z.In this talk, after a short introduction on the methodologies used for computing dipole polarizability (alpha), second and third-order hyperpolarizability and susceptibility; the results of theoretical studies performed on density functional theory (DFT) and ab-initio quantum mechanical calculations of nonlinear optical (NLO) properties for a few selected organic compounds and polymers will be explained. The electric dipole moments (mu) and dispersion-free first hyperpolarizabilities (beta) for a family of azo-azulenes and a styrylquinolinium dye have been determined by DFT at B3LYP level. To reveal the frequency dependent NLO behavior, the dynamic a, second hyperpolarizabilities (gamma), second (chi((2))) and third-order (chi((3))) susceptibilites have been evaluated using time-dependent HartreeFock (TDHF) procedure. To provide an insight into the third-order NLO phenomena of a series of pyrrolo-tetrathiafulvalene-based molecules and pushpull azobenzene polymers, two-photon absorption (TPA) characterizations have been also investigated by means of TDHF. All computed results of the examined compounds are compared with their previous experimental findings and the measured data for similar structures in the literature. The one-photon absorption (OPA) characterizations of the title molecules have been theoretically obtained by configuration interaction (CI) method. The highest occupied molecular orbitals (HOMO), the lowest unoccupied molecular orbitals (LUMO) and the HOMO-LUMO band gaps have been revealed by DFT at B3LYP level for azo-azulenes, styrylquinolinium dye, push-pull azobenzene polymers and by parametrization method 6 (PM6) for pyrrolo-tetrathiafulvalene-based molecules. (C) 2016 Elsevier B.V. All rights reserved.Öğe Calculated hyperfine coupling constants for 5,5-dimethyl-1-pyrroline N-oxide radical products in water and benzene(Maik Nauka/Interperiodica/Springer, 2017) Nardali, S.; Ucun, F.; Karakaya, M.The optimized structures of some radical adducts of 5,5-dimethyl-1-pyrroline N-oxide were computed by different methods on ESR spectra. As trapped radicals, H, N-3, NH2, CH3, CCl3, OOH in water and F, OH, CF3, CH2OH, OC2H5 in benzene solutions were used. The calculated isotropic hyperfine coupling constants of all the trapped radicals were compared with the corresponding experimental data. The hyperfine coupling constant due to the beta proton of the nitroxide radical was seen to be consist with the McConnel's relation alpha(beta) = B (0) + B (1)cos(2)theta and, to be effected with the opposite spin density of oxygen nucleus bonded to the nitrogen. It was concluded that in hyperfine calculations the DFT(B3PW91)/LanL2DZ level is superior computational quantum model relative to the used other level. Also, the study has been enriched by the computational of the optimized geometrical parameters, the hyper conjugative interaction energies, the atomic charges and spin densities for all the radical adducts.Öğe Computational studies on linear and third-order nonlinear optical phenomena of dipolar subunits described for an octupolar system(IEEE Computer Society, 2019) Karakas, A.; Karakaya, M.; Migalska-Zalas, A.; Chtouki, T.; Erguig, H.We have computed the electric dipole moments (μ), dispersion-free and frequency-dependent dipole polarizabilities (α) and third-order hyperpolarizabilities (γ) of dipolar subunits described for an octupolar system (1-3) utilizing time-dependent Hartree-Fock (TDHF) approach. To conceive the nonlinear optical (NLO) phenomena, the third-order susceptibilities (χ(3)) for the title structures have been also derived from the abinitio quantum mechanical procedure (TDHF). According to the computed data on the NLO properties; the cubic hyperpolarizability and susceptibility results of 1-3 are considerably coherent with the measurement values initially produced. © 2019 IEEE.Öğe Computational studies on linear, second and third-order nonlinear optical properties of novel styrylquinolinium dyes(Elsevier, 2016) Karakas, A.; Karakaya, M.; Taser, M.; Ceylan, Y.; Gozutok, A.; Arof, A. K.; El Kouari, Y.The electric dipole moments (mu), static dipole polarizabilities (alpha) and first hyperpolarizabilities (beta) of styrylquinolinium dyes, D8 and D21, have been computed by density functional theory (DFT). The one photon absorption (OPA) characterizations have been investigated using UV-vis spectroscopy and further interpreted using computational chemistry. The time-dependent Hartree-Fock (TDHF) method has been used to describe the dynamic dipole polarizabilities, dynamic second-order and also static and dynamic third-order nonlinear optical (NLO) properties. D8-D21 have rather high beta and second hyperpolarizabilities (gamma). The highest occupied molecular orbitals (HOMO), the lowest unoccupied molecular orbitals (LUMO) and the HOMO-LUMO band gaps for D8-D21 have been evaluated by DFT. (C) 2016 Elsevier B.V. All rights reserved.Öğe Diagnostic and control of linear and nonlinear optical effects in selected self-assembled metallophthalocyanine chlorides nanostructures(Elsevier Sci Ltd, 2018) Zawadzka, A.; Waszkowska, K.; Karakas, A.; Plociennik, P.; Korcala, A.; Wisniewski, K.; Karakaya, M.In this paper we described a new self-assembly phenomenon of the metallophthalocyanine chlorides nanostructures and its influence on the linear optical properties as well as the Second Harmonic Generation process. The self-assembly phenomenon were achieved through an annealing process carried out immediately after the deposition process. The studied nanostructures were subjected to the annealing process for 24 h and the temperature of the process was equal to 525 K. We discussed experimental results and theoretical calculations of structural, linear and nonolinear optical properties for aluminum and gallium phthalocyanine chlorides. The linear and second-order nonlinear optical properties for these compounds were investigated at microscopic and macroscopic levels. The electric dipole moments and dispersion-free first hyperpolarizabilities were determined by quantum chemical calculations based on Density Functional Theory. Ab-initio quantum mechanical calculations (time-dependent Hartree-Fock method) for the studied metallophthalocyanine chlorides were carried out to compute the frequency-dependent first hyperpolarizabilities and second-order susceptibilities at the wavelengths used in SHG measurements. Our results shed light on the linear and nonlinear optical properties of the nanostructures. The results showed that second harmonic signal is strong and polarized, and this polarizing effect was achieved by controlling the arrangement of the molecules inside the formed nanostructures. Our results also reveal potential application of the nanostructures not only for nonlinear optics but also for thermal sensor devices.Öğe Investigations on Stabilities and Intermolecular Interactions of Different Naphthalene Derivatives Dimers by Using B3LYP and M06-2X Density Functional Calculations(Maik Nauka/Interperiodica/Springer, 2014) Karakaya, M.; Cecek, A.; Ucun, F.; Yildiz, M.In this paper, the stabilities and hydrogen bond interactions of 4-chloro-1-naphthol,1-hydrox-ynaphthalene and 1,4-dihydroxynaphthalene dimers have been theoretically investigated by means of study on binding energies with nonlocal hybrid three-parameter Lee-Yang-Parr, B3LYP, and M06-class functional calculations. Calculations on dimers aim to provide as a test of the efficacy of M06 calculations for intermolecular interaction calculations and more strongly bound systems. For hydroxyl-and halo-substituted derivatives of naphthalene, total electronic energies, their correction for the zero point vibrational energies with some calculated thermodynamic properties and their relative differences are together in order to discuss the rotamer structures. Static (hyper) polarizabilities and the electric dipole moments, frontier molecular orbital energy gaps and the relationships between them have been interpreted. Generally, they are seen that the calculated geometric parameters and spectral results were in a good agreement with the corresponding experimental data.Öğe One-photon Absorption Characterizations, Dipole Polarizabilities and Second Hyperpolarizabilities of Chlorophyll a and Crocin(De Gruyter Poland Sp Z O O, 2018) Karakas, A.; Ceylan, Y.; Karakaya, M.; Taser, M.; Terlemez, B. B.; Eren, N.; El Kouari, Y.The dispersion-free dipole polarizability (alpha) computations for chlorophyll a (1) and crocin (2) have been achieved by density functional theory (DFT) at B3LYP/ 6-31G(d) level. The measured one-photon absorption (OPA) wavelengths are quite consistence with the theoretically obtained values. Ab-initio quantum chemical calculations (time-dependent Hartree-Fock (TDHF)) have been implemented to reveal the static second hyperpolarizabilities (gamma) and dynamic dipole polarizabilities of the title molecules. The examined compounds display gamma with non-zero values, introducing their third-order nonlinear optical (NLO) phenomena. The first and second frontier molecular orbitals of the investigated molecules have been also derived from DFT.Öğe Second and third-order nonlinear optical behavior of natural pigment: chlorophyll and crocin(Springer Heidelberg, 2017) Karakas, A.; Karakaya, M.; Taser, M.; Ceylan, Y.; Arof, A. K.; El Kouari, Y.; Sahraoui, B.To provide an insight into the microscopic second and third-order nonlinear optical (NLO) behavior of chlorophyll a and crocin, we have computed the electric dipole moments (mu), dispersion-free first hyperpolarizabilities (beta), frequency-dependent first and second (gamma) hyperpolarizabilities at 1064 nm wavelength area using time-dependent Hartree-Fock (TDHF) method. According to ab-initio calculation results, the examined compounds exhibit first and second hyperpolarizabilities with non-zero values, implying second and third-order NLO phenomena.Öğe Second-order nonlinearities of anionic 3-dicyanomethylen-5,5-dimethyle-1-[2-(4-hydroxyphenyl)ethenyl)]-cyclohexene(Elsevier, 2016) Karakaya, M.; Karakas, A.; Taser, M.; Wolska, N.; Arof, A. K.; Sahraoui, B.Due to the connecting one pi -conjugated group with the two backside donor and acceptor groups, anionic 3-dicyanomethylen-5,5-dimethyle-1-[2-(4-hydroxyphenyl)ethenyl)]-cyclohexene (1) might possess nonlinear optical (NLO) properties. To estimate the potential for second-order NLO behaviour; the electric dipole moments and dispersion-free dipole polarizabilities and first hyperpolarizabilities have been determined by density functional theory (DFT) at B3LYP/6-31++G(d, p) level. Quantum mechanical calculations using time-dependent Hartree-Fock (TDHF) procedure have been utilized to evaluate frequency-dependent second-order nonlinearities of 1. The one-photon absorption (OPA) characterization of 1 has been theoretically obtained by means of configuration interaction (CI) with 6-31G basis set. Our theoretical results on the maximum OPA wavelength, second-order susceptibilities and corresponding microscopic NLO responses are accorded with the previous experimental observations of the investigated compound. The highest occupied molecular orbitals, the lowest unoccupied molecular orbitals and the HOMO-LUMO band gaps for 1 have been also examined by DFT/B3LYP method. (C) 2016 The Authors. Published by Elsevier Ltd.Öğe Structural Characterization and Second-Order Nonlinear Optical Behavior of Metal Complexes of Ferrocene Derivative(Maik Nauka/Interperiodica/Springer, 2019) Deveci, P.; Taner, B.; Ozcan, E.; Kilic, Z.; Karakaya, M.; Karakas, A.In this manuscript, a ferrocene-linked vic-dioxime ligand (LH2) and its metal complexes [Ni(LH)(2), Cu(LH)(2), Co(LH)(2)(H2O)(2), Cd(LH)(H2O)(Cl), and Zn(LH)(H2O)(Cl)] are synthesized, and their structures are studied by spectral methods. Redox behavior of the compounds is studied by cyclic voltammetry (CV). For approaching microscopic second-order nonlinear optical (NLO) behavior of the synthesized ligand and its diamagnetic Cd(II), Zn(II), Ni(II) complexes, the electric dipole moment , static dipole polarizability , and first hyperpolarizability values are computed using ab-initio quantum chemical procedure [finite field (FF)]. The accumulated data indicate that the compounds exhibit non-zero quadratic hyperpolarizability tensor components, implying microscopic NLO phenomena. The HOMOs, LUMOs and the HOMOLUMO band gaps for first and second frontier orbitals of LH2 ligand and its Cd(II), Zn(II), Ni(II) complexes are evaluated by means of the Hartree-Fock (HF) method.Öğe Theoretical Diagnostics of Second and Third-order Hyperpolarizabilities of Several Acid Derivatives(De Gruyter Poland Sp Z O O, 2019) Karakas, A.; Ceylan, Y.; Karakaya, M.; Taser, M.; Terlemez, B. B.; Eren, N.; El Kouari, Y.The density functional theory (DFT) at B3LYP/6-31G(d) level has been utilized to achieve the electric dipole moment (mu), static dipole polarizability (alpha) and first hyperpolarizability (beta) values for ferulic acid (1) and chenodeoxycholic acid (2). The time-dependent Hartree-Fock (TDHF) technique as a powerful quantum chemical method has been implemented to reveal the dynamic alpha, beta and third-order hyperpolarizabilities (gamma) of the examined compounds. Our computational conclusions have been compared with the results of similar materials in the literature. The first and second frontier molecular orbitals (MOs) and their band gaps have also been investigated by means of DFT.Öğe Theoretical investigation of phenazine derivatives by using ab initio calculations(Indian Assoc Cultivation Science, 2014) Yildiz, M.; Karakaya, M.Objective of present study is to compute molecular structures, vibrational frequencies and chemical shifts of phenazine derivatives using density functional theory and Hartree-Fock methods and to compare these results with experimental data. Intramolecular N-Ha <-N interactions have been investigated for stabilization of the molecular conformations. Comparisons of theoretical and experimental data exhibit good correlation confirming the reliability of methods employed in this work. Moreover, frontier orbitals and molecular electrostatic potential have been visualized and calculations of the energy band gaps have been interpreted. According to the results of these investigations, we can say that DFT calculations are significantly stable in electronic structures, spectral, frontier orbitals and electrostatic potential analysis for both the phenazine derivatives.Öğe Theoretical investigations on one-photon absorption wavelengths and first hyperpolarizabilities of dipolar subunits described for an octupolar system(IEEE Computer Society, 2019) Karakas, A.; Karakaya, M.; Migalska-Zalas, A.; Chtouki, T.; Erguig, H.The microscopic second-order nonlinear optical (NLO) phenomena of dipolar subunits described for an octupolar system have been investigated by means of calculating both dispersion-free and also frequency-dependent first hyperpolarizability (β) values from the density functional theory (DFT) and time-dependent Hartree-Fock (TDHF) approaches, respectively. We have estimated the maximum one-photon absorption (OPA) wavelengths by quantum chemical computations utilizing a configuration interaction (CI) technique for the title molecules in the UV area to be lower than 450 nm, indicating well optical transparencies to the visible beam. To find out the optical nonlinearity behaviour describing the molecular orbital structures; the highest occupied molecular orbitals (HOMOs), the lowest unoccupied molecular orbitals (LUMOs) and the HOMO-LUMO energy band gap properties belonging to the first and second frontier MOs have been computationally produced by the DFT procedure. © 2019 IEEE.
