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    Electric quadrupole transition probabilities for singly ionized magnesium
    (PERGAMON-ELSEVIER SCIENCE LTD, 2012) Celik, Gultekin; Dogan, Duygu; Ates, Sule; Taser, Mehmet
    Electric quadrupole transition probabilities for Mg II have been calculated within the weakest bound electron potential model (WBEPM) theory using experimental energy levels and theoretical expectation values of orbital radii corresponding to those energy levels under the assumption of the LS coupling scheme. In this work, the WBEPM theory has been applied to forbidden transitions for the first time. The present results are consistent with earlier theoretical calculations. Some of these results are reported for the first time. (C) 2012 Elsevier Ltd. All rights reserved.
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    Influence of Boron Substitution on the Crystal and Electronic Properties of LiCrO2 Battery Cathode
    (SPRINGER, 2017) Ozkendir, Osman Murat; Ates, Sule; Celik, Gultekin; Klysubun, Wantana
    Boron-substituted LiCrO2 battery cathode material samples were investigated by X-ray-based techniques to probe the influence of boron on their crystal and electronic structure properties. Studies were carried on a series of Li-ion battery cathode materials with the general formula LiCr1-x B (x) O-2. Up to 10 pct boron substitution amounts, light boron atoms were determined to sit in Cr coordinations. However, for more substitutions (> 10 pct), higher electronegativity of boron was determined to govern the crystal structure by obtaining isolated boron-centered domains and built Li2BO4 structures. Electronic structure studies and further crystal structure analysis were carried by X-ray absorption fine structure technique. In the studied samples, increasing boron concentration in the samples (i.e., > 10 pct substitution) were determined to cause a decrease in oxygen bond distances as a result of boron sitting in some chromium locations. As a result of this study, 10 pct boron substitution was determined as a threshold to protect the LiCrO2 crystal structure. (C) The Minerals, Metals & Materials Society and ASM International 2017
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    Investigation of the Effects of Expectation Values for Radii on the Determination of Transition Probabilities using WBEPM Theory
    (INDIAN ACAD SCIENCES, 2008) Celik, Gueltekin; Ates, Sule
    Transition probabilities for some excited s-p and p-s transition arrays of neutral nitrogen have been calculated using the weakest bound electron potential model theory (WBEPMT) for the investigation of effects of expectation values of radii. We have used both numerical non-relativistic Hartree-Fock (NRHF) wave functions and numerical Coulomb approximation (NCA) wave functions to calculate expectation values of radii. The transition probability results obtained using the parameters determined with two different wave functions agree well with each other and accepted values taken from NIST for low values of transition probability. However, the NRHF wave functions present better results for p-s transitions, while NCA wave functions are better in s-p transitions for large values of transition probability.
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    Oscillator strengths and lifetimes for Cu I
    (CANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESS, 2015) Celik, Gultekin; Ates, Sule; Erol, Elmas
    Electric dipole oscillator strengths and lifetimes for Cu I have been calculated within the weakest bound electron potential model theory and the quantum defect orbital theory under the assumption of the LS coupling scheme. In the calculations, many transition arrays including both multiplet and fine-structure transitions are considered. The present results are consistent with earlier theoretical calculations and experimental measurements. Some of these results are reported for the first time.
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    Oscillator strengths and transition probabilities for singly ionized terbium
    (CANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESS, 2014) Ates, Sule; Gokce, Yasin; Celik, Gultekin; Yildiz, Murat
    Electric dipole transition probabilities and oscillator strengths for singly ionized terbium (Tb II) have been calculated with the weakest bound electron potential model (WBEPM) theory using experimental energy levels and theoretical expectation values of orbital radii corresponding to those energy levels under the assumption of the Jj coupling scheme. The transition probabilities and the oscillator strengths calculated have been compared with available data in the literature. A good agreement has been obtained. In this work, the WBEPM theory has been applied to heavy atoms, such as Tb II, for the first time.
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    Theoretical calculations of transition probabilities for individual and multiplet lines between some excited levels of atomic potassium
    (NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS, 2008) Celik, Gueltekin; Ates, Sule
    The transition probabilities for individual and multiplet lines between some excited levels of atomic potassium are calculated using weakest bound electron potential model theory (WBEPMT). The numerical nonrelativistic Hartree-Fock wave functions for the expectation values of radii in all excited states, unlike the Numerical Coulomb Approximation method traditionally used for WBEPMT and experimental ionization energies, have been employed to determine the parameters. The results obtained during this work agree very well with the accepted values taken from National Institute Standards and Technology. Moreover, some transition probabilities not existing on the data bases for highly excited levels in atomic potassium have been obtained using this method.
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    Transition probabilities, oscillator strengths and lifetimes for singly ionized magnesium
    (PERGAMON-ELSEVIER SCIENCE LTD, 2011) Celik, Gultekin; Ates, Sule; Ozarslan, Selma; Taser, Mehmet
    The electric dipole transition probabilities, oscillator strengths and lifetimes have been calculated using the weakest bound electron potential model theory (WBEPMT) for singly ionized magnesium. In the calculations both multiplet and fine structure transitions are studied. We have employed both the numerical Coulomb approximation (NCA) method and numerical non-relativistic Hartree-Fock (NRHF) wave functions for expectation values of radii. The calculated oscillator strengths and lifetimes have been compared with MCHF results given by Fischer et al. (2006). A good agreement has been obtained with the MCHF results. Moreover, some new transition probabilities, oscillator strengths and lifetime values, not existing in the data bases for highly excited levels in singly ionized magnesium, have been obtained using this method. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.