Eur. Phys. J. A (2012) 48: 1
https://doi.org/10.1140/epja/i2012-12001-2

Regular Article - Experimental Physics

Low-spin excitations in ¹⁴⁶Sm

¹ Institut für Kernphysik, Universität zu Köln, 50937, Köln, Germany
² National Institute for Physics and Nuclear Engineering, R-77125, Bucharest-Măgurele, Romania
³ Physics Department, University POLITEHNICA of Bucharest, R-060042, Bucharest, Romania
⁴ Wright Nuclear Structure Laboratory, Yale University, 06520-8124, New Haven, Connecticut, USA

^* e-mail: pascu@ikp.uni-koeln.de

Received: 12 August 2011
Revised: 23 November 2011
Accepted: 7 December 2011
Published online: 20 January 2012

Abstract

The low-spin excitations of the nucleus ¹⁴⁶Sm which is just two neutrons and two protons away from the N = 82 shell and Z = 64 subshell closures have been investigated by means of the ¹⁴³Nd (α, n) and ¹⁴⁴Nd (α, 2n) fusion-evaporation reactions. We established 47 hitherto unknown energy levels up to 4.7MeV and 75 new transitions. In addition, 7 spin assignments were possible from the γ-γ angular correlation analysis. The structure of the possible candidates for a 2⁺ ⊗ 3⁻ quadrupole-octupole multiplet are first discussed in terms of the harmonic vibrational model. A comparison of these states with the corresponding ones in the neighboring N = 84 isotones is also presented. Finally, the structure of the ¹⁴⁶Sm nucleus is interpreted in terms of the IBA-spdf model. It is shown that the model is able to reproduce the experimental relative transition strengths of the 2⁺ ⊗ 3⁻ quadrupole-octupole multiplet and also a series of collective properties such as the proposed double-octupole excitations.