Search for cluster structure of excited states in 14 C

W. von Oertzen; H. G. Bohlen; M. Milin; Tz Kokalova; S. Thummerer; A. Tumino; R. Kalpakchieva; T. N. Massey; Y. Eisermann; G. Graw; T. Faestermann; R. Hertenberger; H.-F. Wirth

doi:10.1140/epja/i2003-10188-9

2021 Impact factor 3.131

Hadrons and Nuclei

Eur. Phys. J. A (2004) 21: 193-215
https://doi.org/10.1140/epja/i2003-10188-9

Search for cluster structure of excited states in ¹⁴ C

W. von Oertzen¹^,2^*, H. G. Bohlen², M. Milin¹^,2^,3, Tz Kokalova¹^,2, S. Thummerer², A. Tumino¹^,2^,4, R. Kalpakchieva⁵^,6, T. N. Massey⁷, Y. Eisermann⁸, G. Graw⁸, T. Faestermann⁹, R. Hertenberger⁸ and H.-F. Wirth⁷

¹ Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195, Berlin, Germany
² Hahn-Meitner-Institut Berlin, Glienicker Strasse 100, D-14109, Berlin, Germany
³ Ruder Bošković Institute, P.O. Box 180, HR-10002, Zagreb, Croatia
⁴ INFN-Laboratori Nazionali del Sud and Universitá di Catania, Via S. Sofia 44, I-95123, Catania, Italy
⁵ Flerov Laboratory of Nuclear Reactions, JINR, RU-141980, Dubna, Russia
⁶ BAS, Institute for Nuclear Research and Nuclear Energy, BG-1784, Sofia, Bulgaria
⁷ Department of Physics and Astronomy, Ohio University, OH 45701-2979, Athens, USA
⁸ Sektion Physik der Universität München, Am Coulombwall 1, D-85748, Garching, Germany
⁹ Technische Universität München, Am Coulombwall 1, D-85748, Garching, Germany

^* e-mail: oertzen@hmi.de

Abstract

We have studied three different 2n-transfer reactions on a ¹²C target, the 2p pick-up reaction on ¹⁶O and the ⁵He transfer in the reaction ⁹Be(⁷Li,d)¹⁴C. Combined with a systematic search through experimental results for transfer reactions, inelastic excitations and other data, we have established an almost complete spectroscopy for ¹⁴C up to 18 MeV excitation. We identify states with single-particle structure that have oblate shapes and states corresponding to proton excitations that are connected to oblate (triangular) cluster states. Further we list states of prolate shape which have no simple structure related to the low-lying oblate states of ¹²C. These are proposed to have strong -clustering and to form rotational bands as a parity inversion doublet, with high moment of inertia. With these results it is possible for the first time to identify chain states expected in the isotope ¹⁴C.