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Öğe Calculation of the infrared frequency and the damping constant (full width at half maximum) for metal organic frameworks(Iop Publishing Ltd, 2019) Kurt, M.; Yurtseven, H.; Kurt, A.; Aksoy, S.The rho(NH2) infrared (IR) frequencies and the corresponding full width at half maximum (FWHM) values for (CH3)(2)(NH2FeMII)-M-III(HCOO)(6) (DMFeM, M = Ni, Zn, Cu, Fe, and Mg) are analyzed at various temperatures by using the experimental data from the literature. For the analysis of the IR frequencies of the rho(NH2) mode which is associated with the structural phase transitions in those metal structures, the temperature dependence of the mode frequency is assumed as an order parameter and the IR frequencies are calculated by using the molecular field theory. Also, the temperature dependence of the IR frequencies and of the damping constant as calculated from the models of pseudospin (dynamic disorder of dimethylammonium (DMA(+)) cations)-phonon coupling (PS) and of the energy fluctuation (EF), is fitted to the observed data for the wavenumber and FWHM of the rho(NH2) IR mode of the niccolites studied here. We find that the observed behavior of the IR frequencies and the FWHM of this mode can be described adequately by the models studied for the crystalline structures of interest. This method of calculating the frequencies (IR and Raman) and FWHM of modes which are responsible for the phase transitions can also be applied to some other metal organic frameworks.Öğe Calculation of the tilt angle and susceptibility as functions of temperature and the electric field close to the Sm A - Sm C* transition in C7(Canadian Science Publishing, Nrc Research Press, 2018) Aksoy, S.; Yurtseven, H.; Kurt, M.Smectic A - Smectic C* transition in the ferroelectric liquid crystal (C7) is studied as a function of the electric field and the temperature. By expanding the free energy in terms of the tilt angle theta (Smectic C* phase) and the polarization P with a linear coupling between theta and P (P theta) in mean field theory, the tilt angle is calculated as a function of the electric field (theta versus E) at constant temperatures with respect to the transition temperature for C7 using the observed data from the literature. Also, by extracting the tilt angle from the observed electric displacements at various temperatures (at constant field strength) the inverse tilt angle susceptibility (chi(-1)(theta)), derived from the free energy, is fitted to the observed data for the dielectric constant and the fitted parameters are determined. Our calculated theta and chi(theta). show that the mean field theory explains adequately the observed behavior of the Smectic A - Smectic C* transition in the liquid crystals C7.Öğe Further Improvements on ?(?*)-ETOs with Hyperbolic Cosine Functions and Their Effectiveness in Atomic Calculations(Elsevier Academic Press Inc, 2013) Aksoy, S.; Firat, S.; Erturk, M.In the last few years, exponential type orbitals became very important in electronic structure calculations of atoms and molecules. In this work, improvements on effectiveness of the psi-exponential type orbitals (psi)-ETOs) (-infinity < 3) containing different hyperbolic cosine functions are presented for the ground states of neutral atoms and their ions. The Hartree Fock Roothaan energies within the minimal basis set framework for some atoms up to Z=18 and their ions are listed and compared with the results obtained with other exponential type orbitals such as conventional double-zeta Slater, noninteger-n Slater with different hyperbolic cosine basis sets and numerical Hartree Fock values. The accuracy of psi-ETOs is greatly improved for all atomic systems studied. The optimal noninteger values of alpha* are determined for each atomic system examined in this work.Öğe Prevalance of Restless Legs Syndrome in Canakkale: A cross-sectional population based study from Northwest of Turkey(Wiley, 2019) Aksoy, S.; Eker, E.; Oymak, S.; Karaman, H. I. Ozisik[Anstract Not Available]Öğe Sm A - ferroelectric-Sm C transition in the mixture of C7+10.O.4 and in the ferroelectric C7(Taylor & Francis Ltd, 2020) Aksoy, S.; Kurt, M.; Yurtseven, H.Tilt angle and the dielectric constant (susceptibility ) as functions of the field strength and temperature, respectively are calculated from the Landau phenomenological model and they are fitted to the observed data from the literature for the Sm A - Sm C* transition in the mixture of C7 + 10.O.4. Values of the critical exponents for the order parameters (tilt angle and polarization P) and tilt angle susceptibility of C7 and of the (dielectric constant) of the mixture C7 + 10.O.4 close to are extracted from the power-law formula. Our results indicate a second-order and a weakly first-order Sm A - Sm C* transitions for C7 + 10.O.4 and C7, respectively as also observed experimentally.
