Azam Kardan

Assistant Professor of Nuclear Physics

  • TEL: +98-2335220090
  • Selected Publications

    Taheri, H., Kardan, A., Hadizadeh Yazdi, M.H. Normal-deformed structures in hafnium isotopes (2018) 98 (5), art. no. 054313, .

    DOI: 10.1103/PhysRevC.98.054313

    The structures of yrast normal-deformed (ND) bands in Hf isotopes have been investigated using the unpaired cranked Nilsson-Strutinsky (CNS), and the paired cranked Nilsson-Strutinsky-Bogoliubov (CNSB) models. New optimized Nilsson parameters have been derived and used in the models to interpret the experimental data in Hf168-175 isotopes. The calculated kinematic moments of inertia, as well as the excitation energies of the yrast bands, have been compared with the experimental findings, and good agreements are observed. Configuration changes along the yrast lines have been traced by the aid of the CNS calculations. The calculated single-particle excitations shed more light on the nature of the crossings and successfully explain some features of the observed rotational bands which had not been clear before. © 2018 American Physical Society.

    PUBLISHER: American Physical Society

    Sayyah, S., Kardan, A. A theoretical study on the triaxial superdeformed and normal deformed wells in Lu isotopes (2017) 2017 (11), art. no. 113D02, .

    DOI: 10.1093/ptep/ptx144

    We have theoretically studied the potential barrier between triaxial superdeformed (TSD) and normal deformed (ND) wells in {161,163,167,168}Lu and {168}Hf nuclei within the framework of the cranked Nilsson-Strutinsky model. We show that the theoretical TSD-ND barrier has disappeared or is narrow or shallow where the experimental TSD-ND electromagnetic transitions are observed, while a theoretical high barrier is seen in nuclei excluding the experimental TSD-ND decay. Also, our calculations show that the barrier between TSD and ND wells decreases with increasing the neutron number. © The Author(s) 2017. Published by Oxford University Press on behalf of the Physical Society of Japan.

    PUBLISHER: Physical Society of Japan

    Kardan, A. Study of Nilsson Potential at different nuclear deformations (2017) 17 (4), pp. 609-613.

    We have studied the Nilsson potential energies at different deformation parameters using a code based on the perturbative treatment. Special attention is given to the projection of a proton state at different deformations on the asymptotic basis functions. Our calculations show that the spin-orbit and the orbital angular momentum terms couple different asymptotic eigenstates, Nilsson Hamiltonian being hence not diagonal in these basis functions. Therefore, at least at deformations ε2≥4.4 IMAGE0.4, the asymptotic quantum numbers are not good quantum numbers. © 2017, Isfahan University of Technology. All rights reserved.

    AUTHOR KEYWORDS: Asymptotic eigenstates; Deformation parameter; Good quantum numbers; Nilsson model; Perturbative treatment
    PUBLISHER: Isfahan University of Technology

    Kardan, A. Nuclear hexacontatetrapole deformation effects on the rotational structures at large deformations in 1 5 8 Er (2017) 26 (7), art. no. 1750044, .

    DOI: 10.1142/S0218301317500446

    Effect of the nuclear hexacontatetrapole deformation on the rotational structure of 158Er is analyzed using the Cranked Nilsson-Strutinsky (CNS) approach. Our calculations show that it will lead to a decrease of the total energy of ∼ 700keV in the strongly deformed (SD) region and only a few keV in the triaxial superdeformed (TSD) region. Therefore, it is concluded that the effect of the hexacontatetrapole deformation is significant for SD shapes and essentially negligible for TSD shapes. © 2017 World Scientific Publishing Company.

    AUTHOR KEYWORDS: 1 5 8 ER; Hexacontatetrapole deformation; unpaired cranked Nilsson-Strutinsky model
    PUBLISHER: World Scientific Publishing Co. Pte Ltd

    Rabizadeh, M., Kardan, A. An unpaired study on the isomeric states 8− and 16+ in178HF (2017) 62 (7-8), art. no. 304, .

    The isomeric states 8− and 16+ in 178Hf are analyzed within the framework of unpaired Cranked Nilsson-Strutinsky (CNS) model including Strutinsky renormalization and the Lublin-Strasbourg Drop (LSD) and Finite Range Liquid Drop (FRLDM) liquid drop methods. Special attention is given to the potential energy surfaces to determine the deformation parameters in the ground and isomeric states. Our calculations show that the hexadecapole deformations in the isomeric states are somewhat larger than those in previous study. Also, the pairing correlation has no effects on the isomeric states shape, while has a significant effects on the excitation energies. © 2017, Editura Academiei Romane. All rights reserved.

    AUTHOR KEYWORDS: 178Hf; Deformation parameters; Isomeric states; LSD and FRLDM models; Unpaired cranked nilsson-strutinsky model
    PUBLISHER: Editura Academiei Romane

    Kardan, A., Nejati, S. Nonaxial hexadecapole deformation effects on the fission barrier (2016) 25 (8), art. no. 1650047, .

    DOI: 10.1142/S0218301316500476

    Fission barrier of the heavy nucleus 250Cf is analyzed in a multi-dimensional deformation space. This space includes two quadrupole (ϵ2,γ) and three hexadecapole deformation (ϵ40,ϵ42,ϵ44) parameters. The analysis is performed within an unpaired macroscopic-microscopic approach. Special attention is given to the effects of the axial and non-axial hexadecapole deformation shapes. It is found that the inclusion of the nonaxial hexadecapole shapes does not change the fission barrier heights, so it should be sufficient to minimize the energy in only one degree of freedom in the hexadecapole space ϵ4. The role of hexadecapole deformation parameters is also discussed on the Lublin-Strasbourg drop (LSD) macroscopic and the Strutinsky shell energies. © 2016 World Scientific Publishing Company.

    AUTHOR KEYWORDS: Fission barrier; nonaxial hexadecapole shapes; unpaired macroscopic-microscopic model
    PUBLISHER: World Scientific Publishing Co. Pte Ltd

    Kardan, A., Sayyah, S. Shape evolution with angular momentum in Lu isotopes (2016) 25 (6), art. no. 1650044, .

    DOI: 10.1142/S0218301316500440

    The nuclear potential energies of Lu isotopes with neutron number N = 90-98 up to high spins are computed within the framework of the unpaired cranked Nilsson-Strutinsky method. The potential and the macroscopic Lublin-Strasbourg drop (LSD) energy-surface diagrams are analyzed in terms of quadrupole deformation and triaxiality parameter. The shape evolution of these isotopes with respect to angular momentum, as well as the neutron number is studied. © 2016 World Scientific Publishing Company.

    AUTHOR KEYWORDS: Cranked Nilsson-Strutinsky method; deformation parameters; LSD model; PES diagram; shape coexistence; shape evolution
    PUBLISHER: World Scientific Publishing Co. Pte Ltd

    Ragnarsson, I., Carlsson, B.G., Kardan, A., Ma, H.-L. Shape coexistence, triaxial shape and band terminations at high spin (2015) 46 (3), pp. 477-486.

    DOI: 10.5506/APhysPolB.46.477

    Selected high-spin bands in A = 120-170 nuclei are interpreted within the configuration-constrained Cranked Nilsson-Strutinsky formalism with pairing neglected (CNS) and with pairing included (CNSB). A few bands in Lu/Hf nuclei which have been interpreted as formed at large triaxial deformation are reinterpreted as rotational bands at small deformation approaching termination. The differences between the linked high-spin rotational bands in 125,126Xe are explored, suggesting that the bands in 126Xe terminate high above yrast at close to spherical shape.

    INDEX KEYWORDS: Physical properties, Band termination; High spins; Rotational band; Shape coexistence; Small deformations; Spherical shape; Triaxial deformation, Deformation
    PUBLISHER: Jagellonian University

    Singh, P., Singh, A.K., Wilson, A.N., Ragnarsson, I., Hübel, H., Bürger, A., Carpenter, M.P., Chmel, S., Fallon, P., Hagemann, G.B., Herskind, B., Ha, H., Janssens, R.V.F., Juhász, K., Kardan, A., Khoo, T.L., Kondev, G., Korichi, A., Lauritsen, T., Nyakó, B.M., Rogers, J., Sletten, G., Timár, J., Zhu, S. High-spin rotational bands in 123I (2012) 86 (6), art. no. 067305, .

    DOI: 10.1103/PhysRevC.86.067305

    High-spin states in 123I were populated in the reaction 80Se(48Ca,p4n)123I at a beam energy of 207 MeV and γ-ray coincidence events were measured using the Gammasphere spectrometer. Three weakly populated, high-spin rotational bands have been discovered with characteristics similar to those of the long collective bands recently observed in other nuclei of this mass region. Configuration assignments are proposed based on calculations within the framework of the cranked Nilsson-Strutinsky approach. ©2012 American Physical Society.
    PUBLISHER: American Physical Society