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Accurate iterative solution of the energy eigenvalues of a two-dimensional hydrogenic donor in a magnetic field of arbitrary strength
(ELSEVIER SCIENCE BV, 2007) Soylu, A.; Boztosun, I.
In this paper, we present the energy eigenvalues of a two-dimensional hydrogenic donor in a magnetic field by using the asymptotic iteration method. The binding energy eigenvalues in the presence of weak and strong magnetic fields (gamma not equal 0) are obtained within the framework of this iterative approach for 1S, 2P(-) and 3D(-) levels. The energy eigenvalues for the non-magnetic field case (gamma = 0) are also determined and the results are compared with the values in weak and strong magnetic fields. The effect of the magnetic field strength on the energy eigenvalues are determined explicitly and excellent agreement with the findings of other methods is obtained. (c) 2007 Elsevier B.V. All rights reserved.
Alpha decay investigations of Bi isotopes
(Indian Assoc Cultivation Science, 2023) Koyuncu, F.; Soylu, A.; Alavi, S. A.; Dehghani, V; Kocak, G.
The alpha decay half-lives of Bismuth isotopes have been investigated systematically by using Wentzel- Kramers-Brillioun (WKB) method and the Bohr-Sommerfeld quantization condition. Three forms of the potentials; Woods-Saxon (WS), Woods-Saxon Squared (WS2) and hybrid potentials have been used to describe the nuclear interaction between the alpha and daughter nuclei. Present results have been compared with the experimental data and results of previous calculations. We have obtained better agreement with the experimental data by using WS2 potential than other potentials.
alpha-alpha folding cluster model for alpha-radioactivity
(SPRINGER, 2015) Soylu, A.; Bayrak, O.
The -decay half-lives are calculated for heavy and superheavy nuclei for and from the ground state to ground state transitions within the framework of the Wentzel-Kramers-Brillouin (WKB) method and the Bohr-Sommerfeld quantization. In the calculations, the - single folding cluster potential obtained with the folded integral of the - potential with the -cluster density distributions is used in order to model the nuclear interaction between the -particle and core nucleus. While the results show very good agreement with the experimental ones in the heavy-nuclei region, especially for even-even nuclei, smaller values than the experimental ones are obtained for superheavy nuclei. As both the density of the core and the interaction term in the folding integral include the -clustering effects and, in this way, all cluster effects are taken into account in the model, the results of calculations are more physical and reasonable than the calculations done in the other models. The present method could be applied to light nuclei with different types of nuclear densities.
An approximate solution of Dirac-Hulthen problem with pseudospin and spin symmetry for any kappa state
(AMER INST PHYSICS, 2007) Soylu, A.; Bayrak, O.; Boztosun, I.
For any spin-orbit quantum number kappa, the analytical solutions of the Dirac equation are presented for the Hulthen potential by applying an approximation to spin-orbit coupling potential for the case of spin symmetry, Delta(r)=C=const, and pseudospin symmetry Sigma(r)=C=const. The bound state energy eigenvalues and the corresponding spinors are obtained in the closed forms.
Asymptotic iteration method solution of the energy spectrum of two-dimensional screened donor in a magnetic field
(ELSEVIER SCIENCE BV, 2008) Soylu, A.; Boztosun, I.
We present the energy spectrum of two-dimensional screened donor for arbitrary magnetic field strength by using the asymptotic iteration method. The binding energy eigenvalues in the presence of the weak and strong magnetic fields (gamma not equal 0) are obtained within the framework of this iterative approach for IS, 2P(-) and 3D(-) ground states. The energy eigenvalues for the non-magnetic field case (gamma = 0) are also determined and the results are compared with the weak and strong magnetic field cases. The effect of the magnetic field strength and different values of the screening parameters on the energy eigenvalues are discussed and the results are compared with findings of the other methods. (C) 2007 Elsevier B.V. All rights reserved.
Binary cluster model calculations for 20Ne and 44Ti nuclei
(World Scientific Publ Co Pte Ltd, 2017) Koyuncu, F.; Soylu, A.; Bayrak, O.
The elastic scattering data of alpha+O-16 and alpha+Ca-40 systems at E-lab = 32.2-146 MeV and E-lab = 24.1-49.5 MeV energies have been analyzed with double-folding (DF) potential in optical model formalism in order to investigate the cluster structures of Ne-20 and Ti-44 nuclei. The deduced DF potentials between alpha and O-16 as well as alpha and Ca-40 have been used for obtaining the excitation energies and alpha-decay widths of Ne-20 and Ti-44 in Gamow code, but the reasonable results could not be obtained. Thus, the real parts of DF potentials which are in the best agreement with experimental data have been fitted with the squared-Woods-Saxon (WS2) potential parameters to calculate the alpha-decay widths of Ne-20 and Ti-44 with Wentzel-Kramers-Brillouin (WKB) approach. The nuclear potential sets obtained in WKB calculations are also used for Gamow code calculations. We take into account the deformation and orientation of Ca-40 nucleus to examine their influence on both the excitation energies and decay widths of Ti-44. Besides, by using the binary cluster model the rotational band energies and electromagnetic transition probabilities (BE2)s according to angles are also reproduced for both nuclei. The obtained results showed that the binary cluster model is very useful to understand the observables of Ne-20 and Ti-44 nuclei. Although only spherical calculations are made for Ne-20 (alpha + O-16), the deformation in Ca-40 would be important for the understanding of Ti-44 (alpha + Ca-40) cluster structure. The mechanism presented here would also be applied to understand the cluster structures in heavy nuclei.
Calculations on the proton decay with modified preformation probability
(World Scientific Publ Co Pte Ltd, 2022) Soylu, A.; Koyuncu, F.; Alavi, S. A.; Dehghani, V.
In this paper, the investigations have been conducted on the half-lives of proton radioactivity of 32 nuclei. The main goal of the paper is to improve the formation probability (S-p) that proposed by Chen et al. [Eur. Phys. J. A 57 (2021) 1]. The obtained results in mentioned paper have been reproduced with uncertainties for all parameters by fitting the experimental data of proton emitters. To carry out the further investigations, we have proposed a new S-p which has a different type of shape from linear. The replacement of the linear form with an exponential, one of the formation probabilities, has affected the rms result positively. The new form of S-p, which has been presented in this study, depends on the mass number of daughter nucleus like the previous one but in exponential form. The obtained findings here may be important for studies while making new predictions.
Cluster decay half-lives using asymmetry dependent densities
(Iop Publishing Ltd, 2022) Dehghani, V; Alavi, S. A.; Razavi, R.; Soylu, A.; Koyuncu, F.
By adopting different neutron and proton density distributions, cluster decay half-lives were investigated using double-folding potentials with constant and nuclear asymmetry dependent sets of nuclear density parameters. Two adopted asymmetry dependent sets of parameters were fitted based on microscopic calculations, and they were calculated based on the neutron skin/halo-type nuclei assumption and by employing experimental rms charge radii. A bulk agreement between theory and experiment was obtained for all sets of parameters using a calculated cluster preformation probability. Few differences were observed between the skin and halo-type assumptions. However, the notable role of the asymmetry parameter was observed in the relatively large differences between the skin and skin-type with zero thickness.
Confinement effects of magnetic field on two-dimensional hydrogen atom in plasmas
(AMER INST PHYSICS, 2015) Bahar, M. K.; Soylu, A.
In this study, for the first time, the Schrodinger equation with more general exponential cosine screened Coulomb (MGECSC) potential is solved numerically in the presence and in the absence of an external magnetic field within two-dimensional formalism using the asymptotic iteration method. The MGECSC potential includes four different potential forms when considering different sets of the parameters in the potential. The plasma screening effects in the weak and strong magnetic field regimes as well as the confinement effects of magnetic field on the two-dimensional hydrogen atom in Debye and quantum plasmas are investigated by solving the corresponding equations. It is found that applying a uniform magnetic field on the hydrogen atom embedded in a plasma leads to change in the profile of the total interaction potential. Thus, confinement effects of magnetic field on hydrogen atom embedded in Debye and quantum plasmas modeled by a MGECSC potential lead to shift bound state energies. This effect would be important to isolate the plasma from the external environment in the experimental applications of plasma physics. (C) 2015 AIP Publishing LLC.
?-decay half-lives of uranium isotopes using a two-potential approach
(Amer Physical Soc, 2024) Alavi, S. A.; Dehghani, V.; Soylu, A.; Koyuncu, F.
Using three methods, the two-potential approach (TPA), the direct method, and the distorted-wave method, the decay widths of uranium isotopes were calculated. Wider ranges of application of the TPA were checked and independence of the decay width to the separation point, from the prebarrier position to the postbarrier position, was observed. The equivalence of the direct and the distorted-wave methods for spherical nuclei was discussed Simplified versions of the TPA and the direct method were used and satisfactory results for the TPA version and the same results for two forms of the direct method were obtained. By presenting different experimental half-lives with remarkable uncertainties, especially for lighter isotopes, the calculated preformation probabilities using the TPA bound wave function and the TPA decay width were compared and reasonable agreement was observed for favored transitions.
Deformation effects on cluster decays of radium isotopes
(ELSEVIER SCIENCE BV, 2015) Soylu, A.; Evlice, S.
We systematically investigate the influence of nuclear deformations of the cluster and daughter nuclei on the half-lives of He-4, Be-8,Be-10, C-12,C-14,C-16 and O-16,O-18,O-20,O-22 cluster decays from Ra210-226. The Wentzel-Kramers-Brillouin (WKB) method and Bohr-Sommerfeld quantization condition with the deformed squared Woods-Saxon and Cosh potentials are used phenomenologically in order to compute the half-lives. The calculations are performed for the spherical cluster and deformed daughter, deformed cluster and spherical daughter and deformed cluster and daughter cases. The half-lives for different orientation angles as well as over all angles are calculated, in order to show the deformation effects on the systems. In cases where the deformation of both cluster and daughter effect the result, it is found that the deformation of the cluster is more important than the deformation of the daughter. Furthermore, it is also found that taking into account the orientation angles of the daughter and cluster also improves the results when compared to experiment. However, the results for a Cosh potential with certain parameters without any deformation are found to be more compatible with both the results obtained by the Coulomb and proximity potential model (CPPM) and the universal formula for cluster decay (UNIV), as well as the experimental values for He-4 and C-14 decays. The results provide a useful method for estimating the unknown experimental half-lives of possible exotic decays from Ra isotopes. (C) 2015 Elsevier B.V. All rights reserved.
Effect of external fields on the energies of hydrogenic donor with the anharmonic confinement potential
(ELSEVIER SCIENCE BV, 2015) Aciksoz, E.; Bayrak, O.; Soylu, A.
The impurity binding energy in the GaAs-Ga1-x AlxAs system is studied with an anharmonic type confinement potential by taking into account the influence of the external electric and magnetic fields within the framework of the effective mass approximation and asymptotic iteration method (AIM). The influence of the external electromagnetic fields and anharmonicity on a donor binding energy is examined systematically. It is shown that the donor binding energy is highly dependent on the external electric and magnetic fields and the confinement potential shapes. Both the electric and magnetic fields are increased, the binding energies increase for each of them. However, the behaviors of increase in the weak and strong fields' regimes have different character a bit. Furthermore, when the more anharmonicity is considered, the binding energy of donor slightly increases as well. (C) 2014 Elsevier By. All rights reserved.
Effect of nuclear deformation on alpha-decay half-lives
(AMER PHYSICAL SOC, 2012) Coban, A.; Bayrak, O.; Soylu, A.; Boztosun, I.
We systematically investigate the influence of nuclear deformations on the alpha-decay half-lives of the deformed medium, heavy, and superheavy nuclei for 106 <= A <= 273 and 52 <= Z <= 110 from the ground state to ground state alpha transitions within the framework of the Wentzel-Kramers-Brillouin (WKB) method by considering the Bohr-Sommerfeld quantization condition. The deformed Wood-Saxon form in a phenomenological way and the deformed Coulomb potential in a special form have been used in order to take into account all deformation effects in the calculations and the preformation of the parent nuclei have also been regarded. Calculations have been conducted for the spherical nuclei in order to present clearly the effects of the deformations on the half-lives. We point out that all considerations have improved the results and very good agreement has been obtained with experimental data.
Effect of the Velocity-Dependent Potentials on the Bound State Energy Eigenvalues
(IOP PUBLISHING LTD, 2011) Bayrak, O.; Soylu, A.; Boztosun, I.
We investigate the effect of isotropic velocity-dependent potentials on the bound state energy eigenvalues for the first time for any quantum states of the Coulomb and harmonic oscillator potentials within the framework of the asymptotic iteration method. When the velocity-dependent term is selected as a constant parameter rho(0), we present that the energy eigenvalues can be obtained analytically for both Coulomb and harmonic oscillator potentials. However, when the velocity-dependent term is considered as a harmonic oscillator type rho(0)r(2), taking the velocity-dependent term as a perturbation, we present how to obtain the energy eigenvalues of the Coulomb and harmonic oscillator potentials for any.. and l quantum states by using perturbation expansion and numerical calculations in the asymptotic iteration method procedure.
Exact solutions of Klein-Gordon equation with scalar and vector Rosen-Morse-type potentials
(IOP PUBLISHING LTD, 2008) Soylu, A.; Bayrak, O.; Boztosun, I.
We obtain an exact analytical solution of the Klein-Gordon equation for the equal vector and scalar Rosen-Morse and Eckart potentials as well as the parity-time ( PT) symmetric version of the these potentials by using the asymptotic iteration method. Although these PT symmetric potentials are non-Hermitian, the corresponding eigenvalues are real as a result of the PT symmetry.
Excitation function measurements of C-12(He-4,Be-8)Be-8, C-12(He-4,C-12[7.65, 0(+)])He-4, and C-12(He-4,C-12[9.64, 3(-)])He-4 reactions
(AMER PHYSICAL SOC, 2012) Soylu, A.; Freer, M.; Ashwood, N. I.; Curtis, N.; Munoz-Britton, T.; Spencer, S.; Wilson, G.
In the present measurements a C-12 target was bombarded by a He-4 beam with energies from 14 to 21 MeV and the excitation function measurements for the reactions of the C-12(He-4, Be-8)Be-8, C-12(He-4, C-12[7.65, 0(+)])He-4, and C-12(He-4, C-12[9.64, 3(-)])He-4 were obtained using an array of 6 double-sided silicon strip detectors. The excitation functions are used to gain an insight into possible a-cluster structures in O-16.
Experimental study of high-lying states in Mg-28 using the resonant elastic scattering of alpha particles
(AMER PHYSICAL SOC, 2016) Walshe, J.; Freer, M.; Wheldon, C.; Soylu, A.; Achouri, N. L.; Ashwood, N. I.; Marques, F. M.
The excitation function of Mg-28 above the alpha-decay threshold has been measured for the first time using the resonant scattering of alpha particles with the technique of a thick target in inverse kinematics. Thirteen new states are reported between E-x = 15.5 and E-x = 20.5 MeV, and suggestions for spin-parity assignments are given for two of these. Calculations of the branching ratio to a decay for these states as well as comparison of the measured cross sections to calculations suggest that alpha + Ne-24(g.s). clustering is not dominant in this energy regime.
Generalized potential for confined positronium atom immersed in plasmas
(Elsevier, 2020) Bahar, M. K.; Soylu, A.
We suggest, for the first time, the more general exponential cosine screened Coulomb (MGECSC) potential to investigate the positronium (Ps) atom immersed in Debye and quantum plasmas. Ps atom immersed in Debye and quantum plasmas under spherical confinement is examined by solving the corresponding Schrodinger equation via the tridiagonal matrix method. The MGECSC potential has four different sets to model Debye and quantum plasmas. But, we consider only two sets as the screened Coulomb (SC) potential for Debye plasma and the MGECSC potential for quantum plasma. The results of the confinement and the plasma screening effects on the energies, radial matrix elements, dipole polarizabilities and oscillator strengths of Ps atom are obtained, discussing in detail. It is worthwhile to specify that the spectroscopic features of Ps atom located in only plasma environment enable detailed information about plasma environment. The MGECSC potential is proposed to model various interactions of Ps atom immersed in plasma environment. In this study, the necessity and details of the MGECSC potential is discussed.
Heavy ion fusion reaction cross section: Analysis of the temperature dependence of the repulsive nuclear potential
(Amer Physical Soc, 2020) Ghorbani, F.; Alavi, S. A.; Dehghani, V; Soylu, A.; Koyuncu, F.
Using the Wong formula, fusion cross sections of O-18+ Cu-63, O-18+ Pt-194, O-16+ Pb-208, and C-12+ Pr-141 reactions are calculated with double-folding potentials (M3Y) and inclusion of the corrected temperature-dependent repulsive nuclear potential (M3Y + rep). Two different values of repulsive diffuseness are selected in calculations and effect of nuclear temperature on the repulsive nuclear potential, the effective potential, and three parameters of the Wong formula are investigated. Our results show that the inclusion of temperature-dependent repulsive nuclear potential increases the effective potential in interior regions, noticeably. However, in the near-barrier region, little enhancement of the effective potential causes small variations in the barrier height, position, and frequency. Better agreement between theory and experiment is observed by including the repulsive nuclear potential.
Higher twist effects in proton-proton collisions
(WORLD SCIENTIFIC PUBL CO PTE LTD, 2006) Ahmadov, A. I.; Boztosun, I.; Muradov, R. Kh.; Soylu, A.; Dadashov, E. A.
In this article, we investigate the contribution of the high twist Feynman diagrams to the large-P-T pion production cross section in proton-proton collisions and we present the general formulae for the high and leading twist differential cross sections. The pion wave function where two non-trivial Gegenbauer coefficients a(2) and a(4) have been extracted from the CLEO data, two other pion model wave functions, P-2, P-3, the asymptotic and the Chernyak-Zhitnitsky wave functions are used in the calculations. The results of all the calculations reveal that the high twist cross sections, the ratios R, r, the dependence transverse momentum P-T and the rapidity y of pion in the Phi(CLEO)(x, Q(2)) wave function case is very close to the Phi(asy) (x) asymptotic wave function case. It is shown that the high twist contribution to the cross section depends on the choice of the meson wave functions.

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