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Öğe Ab-Initio Calculations on Static and Dynamic Third-Order Optical Nonlinearity of Azo-Azulenes(2012) Karakaş, A.; Kouari, Y. E.; Migalska-Zalas, A.; Sahraoui, B.To provide an insight into the microscopic third-order nonlinear optical (NLO) behavior of a series of azo-azulenes; both dispersion-free (static) and also frequency-dependent (dynamic) linear polarizabilities (?) and second hyperpolarizabilities (?) at 532nm wavelength have been theoretically investigated by means of a time-dependent Hartree-Fock (TDHF) method. The maximum one-photon absorption (OPA) wavelengths recorded by quantum mechanical computations using a configuration interaction (CI) method are estimated in the visible region, supporting the ???* transitions. The ab-initio calculation results with non-zero values on (hyper)polarizabilities indicate that the title compounds might possess microscopic third-order NLO phenomena.Öğe Comparison between Quantum Mechanical Computations of NLO Properties and Experimental Data in Selected Functionalized Azo-Dyes(IEEE, 2012) Sahraoui, B.; Karakas, A.; Hajjaji, A.; El Kouari, Y.; Migalska-Zalas, A.Nonlinear optical (NLO) materials have been extensively studied for many years. The search of new materials with NLO properties is an important research field. Significant interest still exists in the design and development of materials exhibiting large second and third-order NLO response because of the potential application in optoelectronics devices [1-2]. In this talk, comparison between quantum mechanical computations of NLO properties and experimental data in selected azo-dyes will be done. Particularly we will focus on correlation between macroscopic level and microscipic one. To reveal the microscopic second-order NLO properties of a family of azo-azulenes, the electric dipole moments (mu) and static first hyperpolarizabilities (beta) have been evaluated by using density functional theory (DFT) quantum mechanical calculations at B3LYP/6-311+G (d, p) level. The calculation results with non-zero values on first hyperpolarizabilities indicate that the title molecules might possess microscopic second-order NLO phenomena. The maximum one-photon absorption (OPA) wavelengths obtained by theoretical computations using the configuration interaction (CI) method are located in the visible region, supporting the pi -> pi* transitions. We have also calculated the dynamic second (chi((2))) and third-order chi((3)) susceptibilities using the time-dependent Hartree-Fock (TDHF) method.Öğe Determination of Dipole Polarizabilities and Second Hyperpolarizabilities in Alkynyl-Ruthenium Complexes Using Quantum-Chemical Calculations(IEEE, 2013) Karakas, A.; Dag, T.; Migalska-Zalas, A.; Fillaut, Jean-Luc; Sahraoui, B.To investigate dispersion-free third-order nonlinear optical (NLO) behaviour of a series of ruthenium complexes, static dipole polarizabilities (alpha) and second hyperpolarizabilities (gamma) have been determined by time-dependent Hartree-Fock (TDHF) method. To provide an insight into the frequency-dependent third-order NLO phenomena of the title compounds, the dynamic dipole polarizabilities and second hyperpolarizabilities using TDHF procedure have been also computed at the wavelengths used in third-harmonic generation (THG) measurements. According to the computation results, the examined molecules exhibit second hyperpolarizabilities with non-zero values, implying microscopic third-order NLO behaviour. To compare our theoretical results on third-order NLO manner with corresponding experimental data, we also give the calculation results of the dynamic third-order susceptibilities (X-(3)) for the studied complexes.Öğe The Investigation of Third-Order Hyperpolarizabilities and Susceptibilities of Push-Pull Azobenzene Polymers(IEEE, 2013) Karakas, A.; EL Ouazzani, H.; Kirkan, N.; Krupka, O.; Smokal, V.; Migalska-Zalas, A.; Sahraoui, B.To estimate the potential for third-order nonlinear optical (NLO) properties of the title azobenzene polymers, the one-photon absorption (OPA) and two-photon absorption (TPA) characterizations have been determined by configuration interaction (CI) and time-dependent Hartree-Fock (TDHF) methods, respectively. The nonlinear absorption parameters (beta) and third-order susceptibilities (chi((3))) have been measured by performing the Z-scan measurements. According to the ab-initio computation results, the investigated compounds exhibit averaged (isotropic) second hyperpolarizabilities () with non-zero values, implying microscopic third-order optical nonlinearity. Our computed results on TPA cross-sections (delta(omega)), third-order hyperpolarizability and susceptibility values are in accord with the experimental observations of the examined molecules.Öğe Quantum chemical calculations and experimental studies of third-order nonlinear optical properties of conjugated TTF-quinones(ELSEVIER SCIENCE BV, 2013) Karakas, A.; Migalska-Zalas, A.; El Kouari, Y.; Gozutok, A.; Karakaya, M.; Touhtouh, S.To investigate microscopic third-order nonlinear optical (NLO) behaviour of two tetrathiafulvalene (TTF) derivatives, TTF-diquinone triad (1) and TTF-monoquinone dyad (2), we have computed both dispersion-free and also dispersion of dipole polarizabilities (alpha) and third-order hyperpolarizabilities (gamma) at 532 nm wavelength using time-dependent Hartree-Fock (TDHF) method. The one-photon absorption (OPA) characterizations of the title molecules have been theoretically obtained by means of configuration interaction (CI) method with all doubly occupied molecular orbitals. We have also calculated the dynamic third-order susceptibilities (chi((3))) using the TDHF method. Our theoretical results on the maximum OPA wavelengths, third-order susceptibilities and corresponding microscopic NLO responses are in good agreement with the previous experimental observations of the examined TTF-based molecules. The highest occupied molecular orbitals (HOMO), the lowest unoccupied molecular orbitals (LUMO) and the HOMO-LUMO band gaps for I and 2 have been evaluated by density functional theory (DFT) quantum mechanical calculations at B3LYP/6-31 G(d,p) level. (C) 2013 Elsevier B.V. All rights reserved.Öğe Second-Order Hyperpolarizability and Susceptibility Calculations of a Series of Ruthenium Complexes(IEEE, 2013) Karakas, A.; Dag, T.; Taser, M.; Fillaut, J-L; Migalska-Zalas, A.; Sahraoui, B.The ab-initio quantum mechanical calculations (time-dependent Hartree-Fock (TDHF) method) of a series of ruthenium complexes have been carried out to compute electric dipole moment (mu), dispersion-free and frequency-dependent first hyperpolarizability (beta) values. The one-photon absorption (OPA) characterizations have been also theoretically investigated by means of configuration interaction (CI) method. Our calculated results on the maximum OPA wavelengths and second-order hyperpolarizabilities are in good agreement with the observed values in the literature. According to the results of the TDHF calculations, the investigated molecules exhibit non-zero beta values, and they might have microscopic second-order nonlinear optical (NLO) behaviour. We also give the computational results of the frequency-dependent second-order susceptibilities (X-(2)) for the examined compounds. The calculated results on dynamic (X-(2)). are quite consistent with the previous experimental observations.
