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Öğe Computation of Energy States of Hydrogenic Quantum Dot with Two-Electrons(AMER INST PHYSICS, 2016) Yakar, Y.; Ozmen, A.; Cakir, B.In this study we have investigated the electronic structure of the hydrogenic quantum dot with two electrons inside an impenetrable potential surface. The energy eigenvalues and wavefunctions of the ground and excited stales of spherical quantum dot have been calculated by using the Quantum Genetic Algorithm (QGA) and Hartree-Fock Roothaan (IIFR) method, and the energies are investigated as a function of dot radius. The results show that as dot radius increases, the energy of quantum dot decreases.Öğe EPR study of gamma-irradiated amphi-phenylglyoxime single crystals(PERGAMON-ELSEVIER SCIENCE LTD, 2011) Dereli, O.; Turkkan, E.; Ozmen, A.; Yuksel, H.Gamma-irradiated single crystals of Amphi-phenylglyoxime (APGO) were investigated using electron paramagnetic resonance (EPR) at different orientations in a magnetic field at room temperature (298 K). Considering the chemical structure and the experimental spectra of the irradiated single-crystals of APGO, we assumed that two different paramagnetic species, labeled as R* and R**, are either two iminoxy radicals formed by the abstraction of a H atom from different oxime branches or are different conformations of an iminoxy radical. Pursuant to this assumption, RA- and RB-type iminoxy radicals were modeled by the abstraction of H atoms from different oxime branches, and conformational analysis of these modeled radicals was performed using the semi-empirical AM1 and B3LYP/6-31 +G(d,p) methods. EPR parameters were calculated for the modeled radicals using the B3LYP method and EPR-III basis set. Theoretically calculated values of the most stable conformers (RA-1 and RB-1) of the modeled radicals are in good agreement with the experimental EPR parameters determined from the spectra (differences in isotropic hyperfine coupling constant values <5%, and differences in isotropic g values fall into 1 ppt). Thus, from the findings of the present study, we strongly suggest that the experimentally observed R* and R** radicals in the single crystal of amphi-phenylglyoxime are the most stable conformers of RA- and RB-type modeled iminoxy radicals, respectively. The experimental g factors and hyperfine coupling constants were found to be anisotropic, with average values of g=2.0052, A(N-14)=29.50 G, A(H-1)=25.30 G for R*, and g=2.0057, A(N-14)=34.50 G for R**. (C) 2011 Elsevier Ltd. All rights reserved.Öğe Molecular Structure and Vibrational Spectra of Alpha-Benzoinoxime by Density Functional Method(MAIK NAUKA/INTERPERIODICA/SPRINGER, 2014) Dereli, O.; Erdogdu, Y.; Gulluoglu, M. T.; Sundaraganesan, N.; Turkkan, E.; Sayin, U.; Ozmen, A.In the present study, an exhaustive conformational search of the Alpha-benzoinoxime has been performed. The FT-IR spectrum of this compound was recorded in the region 4000-400 cm(-1). The FT-Raman spectrum was also recorded in the region 3500-50 cm(-1). Vibrational frequences of the title compound were calculated by B3LYP method using 6-311++G(d, p) basis set. The calculated vibrational frequences were analysed and compared with experimental results.Öğe Radiation Damage Centers in Cholesteryl Heptanoate(POLISH ACAD SCIENCES INST PHYSICS, 2013) Sayin, U.; Can, C.; Turkkan, E.; Dereli, O.; Ozmen, A.; Yuksel, H.Cholesterol takes part significantly in many biological mechanisms and as important component for manufacture of bile acids, steroid hormones, and several fat-soluble vitamins. To determine magnetic properties of cholesteryl heptanoate (C34H58O2) which is an important cholesteryl ester in human life and new technology, the single crystals of cholesteryl heptanoate were grown by slow evaporation of concentrated ethyl acetate solution and the grown single crystals were irradiated at room temperature with Co-60 gamma ray. The radical produced by gamma irradiation has been investigated in the range of temperatures 123-330 K for different orientations of the crystal in a magnetic field by EPR. Radiation damage center was attributed to radical (C) over dotH(alpha)CH(2 beta). The g factor and hyperfine coupling constants have slight dependence on temperature and evident dependence on the orientation of the magnetic field. Determined g factor and hyperfine coupling constants for the radical (C) over dotH(alpha)CH(2 beta) were found to be anisotropic with the average values g(av) = 2.0036, (a(CH alpha))(av) = 14.52 G, (a(CH2 beta))(av) = 25.78 G.Öğe A theoretical study about factors affecting conformational stabiltiy order of glyoxime(SILA SCIENCE, 2011) Dereli, O.; Cavusoglu, H.; Turkkan, E.; Ozmen, A.; Ilik, A.In this study, stable conformers and the effects determining conformational stability of the glyoxime (GO) molecule are inspected. Semiemprical PM3 method is used for conformer distribution. Geometry optimizations are performed by MP2/6-311++G(d,p) level of theory. We obtained twenty stable conformers for the title compound; however conformer 1 is (approximately 17 kcal/mol) more stable than conformer 20. Calculated geometry parameters for the most stable conformer are consistent with experimental results. Long range electrostatic, conjugation, and hydrogen bonding effects are found responsible for stability order of GO. Four conformers which can be determined experimentally are isolated theoretically. Thermodynamic and geometrical parameters of these isomers are given first time in this study. Calculated relative energies of these conformers are very close to each other. For this reason, isolation of these conformers is very difficult for experimentalists. The chemical reactivities of GO conformers were investigated by HOMO-LUMO energy gaps.Öğe Zeeman Transitions In Spherical Quantum Dot(AMER INST PHYSICS, 2017) Yakar, Y.; Cakir, B.; Yilmazer, F.; Ozmen, A.In this study, the effects of external magnetic field on the energy states of a spherical quantum dot With infinite potential harrier have been investigated by using Quantum Genetic Algorithm (QGA) and Hartree-Fock Roothaan (HFR) method. Linear Zeeman states and Zeeman transition energies are calculated as a function of dot radius and magnetic field strength. We also carry out the effect of external magnetic field on the ground state binding energy. The results show that the impurity energy states, binding energy and Zeeman transition energies are strongly affected by magnetic field strength and dot radius.
