Eur. Phys. J. A (2016) 52: 340
https://doi.org/10.1140/epja/i2016-16340-6

Regular Article - Experimental Physics

Collective 2⁺ ₁ excitations in ²⁰⁶Po and ^208,210Rn

¹ University of Jyvaskyla, Department of Physics, P.O. Box 35, FI-40014, Jyvaskyla, Finland
² Helsinki Institute of Physics, P.O. Box 64, FI-00014, Helsinki, Finland
³ Institut für Kernphysik, Universität zu Köln, 50937, Köln, Germany
⁴ Institut für Kernphysik, TU Darmstadt, 64289, Darmstadt, Germany
⁵ Wright Nuclear Structure Laboratory, Yale University, P.O. Box 208120, 06520-8120, New Haven, CT, USA
⁶ Department of Physics, Oliver Lodge Laboratory, University of Liverpool, L69 7ZE, Liverpool, UK
⁷ Université de Genève, 24 Quai Ernest-Ansermet, CH-1211, Genève 4, Switzerland
⁸ Instituut voor Kern- en Stralingsfysica, Department of Physics, KU Leuven, 3001, Leuven, Belgium
⁹ School of Engineering, University of the West of Scotland, PA1 2BE, Paisley, UK
¹⁰ CERN-ISOLDE, PH Department, CERN, CH-1211, Geneva 23, Switzerland
¹¹ CEA-Saclay, 91191, Gif-sur-Yvette, France
¹² Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11, Bratislava 45, Slovakia
¹³ Department of Physics, University of York, YO10 5DD, York, UK

^* e-mail: tuomas.grahn@jyu.fi

Received: 29 July 2016
Accepted: 28 October 2016
Published online: 22 November 2016

Abstract

In the present study, values have been measured in the ^208,210Rn and ²⁰⁶Po nuclei through Coulomb excitation of re-accelerated radioactive beams in inverse kinematics at CERN-ISOLDE. These nuclei have been proposed to lie in, or at the boundary of the region where the seniority scheme should persist. However, contributions from collective excitations are likely to be present when moving away from the N=126 closed shell. Such an effect is confirmed by the observed increased collectivity of the transitions. Experimental results have been interpreted with the aid of theoretical studies carried out within the BCS-based QRPA framework.