RESEARCH ARTICLE European Journal of Applied Physics www.ej-physics.org DOI: http://dx.doi.org/10.24018/ejphysics.2021.3.5.106 Vol 3 | Issue 5 | October 2021 34 I. INTRODUCTION In the collective model proposed by Bohr and Mottelson [1], a new parameter called nuclear deformation is introduced, in which the surface of the nucleus may undergo oscillations in a rotating nucleus. These results in the prediction of rotational energy levels being restricted to even values due to oscillating symmetry and it is easily observed with nuclei having a number of nucleons far from closed shells. Experimental data comes to a good agreement with these predictions, and applications such as probability for B(E2) transitions, magnetic moments, quadrupole moments and isomeric transitions are so far successful. In the macroscopic interpretation, the common simplest preliminary point of modeling the atomic nucleus is based on liquid drop model [2], [ 3] where the nucleus is assumed to behave a drop of dense incompressible liquid where the spherical shape is the result of attractive forces between all the particles contained in the nucleus. This model is then prolonged to explain quantum mechanical collective motion, for example vibrations and rotation, which is developed to the Bohr and Mottelson collective model [1]. In these models, a new parameter called nuclear deformation is introduced, in which the surface of the nucleus may undergo oscillations in a rotating nucleus [4]. These results in the prediction of rotational energy levels being restricted to even values due to oscillating symmetry, and it is easily observed with nuclei having a number of nucleons far from closed shells. There are lots of theoretical and experimental methods for rotational nuclei found in the literature. Jett et al. [5] were observed rotational band of Dysprosium (Dy), Erbium (Er), Ytterbium (Yb) and Hafnium (Hf) nuclei with neutron number 92, 96, 98, 102, respectively by excitation with neutron vaporization techniques. Panel et al.[6] studied rotational bands of low-level quasi-particle photon coupling plus rotor model of the 169Er nucleus. Shimada et al [7] have been studied rotational motion of triaxially deformed nuclei using the microscope angular momentum method. Ghorui et al. [8] studied the rotational bands and electromagnetic transitions of some even- even Neodymium nuclei in J- Projected Hartree-Fock Model Kassim et al. [9], [10] have Rotational Ground-State Bands of 168 Hf Nucleus I. Hossain, Hewa Y. Abdullah, M. A. Saeed, M.O. Alzanbaqi, and Fadhil I. Sharrad ABSTRACT This paper has been explained to study the rotational arrangement of even-even 168 Hf isotope using the phenomenological fitting, Sood’s semi- empirical formula. The rotational energies from the calculated values were compared to the experimental data. The result shows that in 168 Hf, calculated energies fit the experimental values to a remarkable degree of accuracy. Keywords: Rotational energy, semi-empirical formula, 168 Hf, Yrast state. Published Online: October 05, 2021 ISSN: 2684-4451 DOI :10.24018/ejphysics.2021.3.5.106 I. Hossain* Department of Physics, Rabigh college of Science & Arts, King Abdulaziz University, Saudi Arabia. (e-mail: mihossain kau.edu.sa) Hewa Y. Abdullah physics Education Department, Faculty of Education, Tishk International University, Iraq. (e-mail: kuhewa yahoo.com) M. A. Saeed Department of Physics, Division of Science & Technology, University of Education, Pakistan. (e-mail: moalsd gmail.com) M. O. Alzanbaqi Department of Physics, Rabigh college of Science & Arts, King Abdulaziz University, Saudi Arabia. (e-mail: moalznbaki kau.edu.sa) Fadhil I. Sharrad Department of Physics, College of Education, Kerbala University, Iraq. College of Health and Medical Technology, Al-Ayen University, Iraq. (e-mail: fadhil.altaie gmail.com +) *Corresponding Author @ @ @ @ @