Eur. Phys. J. A (2009) 39: 323-333
https://doi.org/10.1140/epja/i2008-10722-3

Regular Article - Theoretical Physics

Low-lying magnetic and electric dipole strength distribution in the ¹⁷⁶Hf nucleus

¹ Institute of Physics, Academy of Sciences, H. Cavid Avenue 33, Baku, Azerbaijan
² Physics Department, Faculty of Arts and Sciences, Sakarya University, 54100, Adapazari, Turkey
³ Institut fur Kernphysik, Technische Universitat Darmstadt, Darmstadt, Germany

Received: 1 July 2008
Revised: 15 January 2009
Accepted: 17 January 2009
Published online: 19 February 2009

Abstract

In this study the QRPA approach with the rotational and translational invariant Hamiltonians has been carried out to describe magnetic and electric dipole excitations in ¹⁷⁶Hf . Calculations show that the ¹⁷⁶Hf nucleus demonstrates a very rich B(M1) strength structure and in some aspects nicely confirm the experimental data. It has been shown that the main part of spin-1 states, observed at 2-4MeV in ¹⁷⁶Hf , may be attributed to have a M1 character and may be interpreted as the main fragments of the scissors mode. The agreement between the calculated mean excitation energies as well as the summed B(M1) values of the scissors mode excitations and the available experimental data is quite good. The constructive interference between the orbit and the spin part of M1 strength has been found to be below 3.5MeV. The calculations indicate the presence of a few prominent negative-parity states in the 2-4MeV energy interval. This suggests that the supposition of the experiment “all stronger K = 1 low-lying dipole excitations were of magnetic character” cannot be generalized.