Document Type : Research paper

Authors

• M. Moonesi
• S. Mohammadi
• M. Shahriari

Department of Physics, Payame Noor University, PO BOX 19395-3697 Tehran, Iran

Abstract

This paper has calculated the energy levels of 185-187-189Os isotopes using the projected shell model (PSM). Yrast Spectrum, nucleus rotation frequency and the ratio of reduced electromagnetic transition probabilities, B(E2)/B(M1) plots versus spin for understanding the structure of multi-quasiparticle band up to the spins 47/2⁺, 33/2⁺ and 31/2⁺ for these isotopes, are plotted, respectively. It was found that in the spin ranges 35/2⁺-39/2⁺, 31/2⁺-33/2⁺, and 27/2⁺-29/2⁺, due to 3-quasiparticle band-crossing, simultaneously by increasing rotational inertia of the nucleus, nucleus rotation frequency decreases greatly and as an important result, B(E2)/B(M1) ratio, the electrical properties of the nucleus in these spins increase. Indeed, in these isotopes, observed that by increasing neutron number, the deformation parameter, ε₂ decreases as well, and by increasing spin in especial spins, due to nucleon alignment phenomenon, the nucleus rotational behavior decreases inverse the vibration mode.  

Keywords

• Yrast Spectrum
• Alignment Phenomenon
• Electromagnetic Transition Probability
• Projected Shell Model

Main Subjects

• NUCLEAR PHYSICS AND RADIATION PHYSICS