Eur. Phys. J. A 12, 129-133 (2001)
First measurements of yrast excitations in 137I
and the missing 12+ isomer in 136Te
A. Korgul1, W. Urban1, T. Rzaca-Urban1, M. Górska2, J.L. Durell3, M.J. Leddy3, M.A. Jones3, W.R. Phillips3, A.G. Smith3, B.J. Varley3, M. Bentaleb4, E. Lubkiewicz4, N. Schulz4, I. Ahmad5 and L.R. Morss5
1 Institute of Experimental Physics, Warsaw University, ul.Hoza 69, 00-681 Warszawa, Poland
2 Instituut voor Kern- en Stralingsfysica, Katholieke Universiteit Leuven, B-3001 Heverlee, Belgium
3 Schuster Laboratory, Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
4 Institut de Recherches Subatomiques UMR7500, CNRS-IN2P3 and Université Louis Pasteur, 67037 Strasbourg, France
5 Argonne National Laboratory, Argonne, IL 60439, USA
(Received: 6 June 2001 / Revised version: 23 September 2001 Communicated by D. Schwalm)
The 137I nucleus, populated in the spontaneous fission of 248Cm has been studied by means of prompt -ray spectroscopy using the EUROGAM2 array. Medium-spin yrast excitations in 137I were observed for the first time. The experimental level scheme is compared to the shell model calculation with modified Kuo-Herling interaction. The theoretical predictions differ significantly from the experimental results, indicating that the excitation pattern in 137I deviates significantly from the shell model scheme.
23.20.Lv - Gamma transitions and level energies.
21.60.Cs - Shell model.
25.85.Ca - Spontaneous fission.
27.60.+j - .
© Società Italiana di Fisica, Springer-Verlag 2001