Magnetic dipole response of the Tm-169 nucleus

Abstract

The magnetic dipole (M1) response of the Tm-169 nucleus is investigated from a theoretical point of view. The theoretical tool used in this study is the Rotational Invariant Quasiparticle Phonon Nuclear Model (RI-QPNM) which gives a possibility to eliminate spurious contributions in the M1 spectrum. In the frame-work of this model, both the low-lying and high-lying parts of the M1 excitation spectrum of Tm-169 are calculated. The result shows that the low-lying excitations have almost pure orbital character and can be interpreted as scissors mode, whereas the high-lying transitions can be read as spin-flip mode because of its spin nature. The reduced transition probability summed up in the energy range 2-4 MeV is found to be B(M1 up arrow) = 3.040 mu(2)(N) which agrees with the available experimental data. The fragmentation of the low-energy M1 strength is also well reproduced. This is also the first study in which both the low-lying and high-lying M1 spectrum of the Tm-169 nucleus is theoretically investigated. (C) 2018 Elsevier B.V. All rights reserved.