Mehmet Taşer

Second-order hyperpolarizability and susceptibility calculations of a series of ruthenium complexes

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 (μ), dispersion-free and frequency-dependent first hyperpolarizability (β) 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 β 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 (χ(2)) for the examined compounds. The calculated results on dynamic (χ(2)) are quite consistent with the previous experimental observations.

Z-scan determination and ab-initio computations on third-order optical nonlinearities of a styrylquinolinium dye

In order to elucidate the third-order nonlinear optical (NLO) phenomena of the styrylquinolinium dye (1), the nonlinear absorption parameter (ß) and third-order susceptibility (χ(3)) have been measured using the Z-scan measurements. 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 averaged (isotropic) second hyperpolarizability (〈γ〉) allows the determination of the third-order optical response. The ab-initio calculation on 〈γ〉 with non-zero value reveals that the title dye has relatively good third-order NLO properties. The calculated results of 1 on OPA wavelength, TPA cross-section (δ(ω)) and third-order susceptibility are in reasonable agreement with its experimental data.