Browsing by Author "Ates T."

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    An experimental and theoretical investigation of the structure of synthesized ZnO powder
    (2018-09-24) Kaygili O.; Ercan I.; Ates T.; Keser S.; Orek C.; Gunduz B.; Seckin T.; Bulut N.; Bañares L.
    ZnO powder has been synthesized, characterized experimentally and its theoretical modeling carried out by density functional theory (DFT). The experimental and theoretical results were compared with each other and with the available data in the literature. A detailed crystal structure analysis was carried out using X-ray diffraction (XRD) data. Experimental and theoretical FTIR analysis, energy gap and density of states and electronic band structure calculations have been done for a complete characterization of the material. The surface morphology has been investigated by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. It has been found that the electron excitation of ZnO can occur most probably at the Γ-Γ point, where the energy gap has the lowest value between the valance and conduction bands.
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    Temperature dependent structural and vibrational properties of hydroxyapatite: A theoretical and experimental study
    (2017-12-01) Kebiroglu M.H.; Orek C.; Bulut N.; Kaygili O.; Keser S.; Ates T.
    We describe the temperature dependence of the vibrational, rotational and translational partition functions of the activated complex of hydroxyapatite (HAp). Computed data show that the vibrational modes have a larger contribution towards the partition function of HAp compared to the rotational and translational contributions. X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy have been applied for HAp in the temperature range from 730 °C to 1030 °C at steps of 100 °C. Temperature dependent density functional theory (DFT), B3LYP, and Ground State Hartree-Fock (HF) with 6–311G basis set calculations were also applied to HAp to calculate FTIR spectra, HOMO, and LUMO energies, and density of states (DOS), and the results have been compared to experimental findings. The present results underline that experimental measurements and theoretical calculations of unit cell parameters, and the intensities of most of the FTIR data for HAp are nearly independent on temperature.