Nuclear Physics A427 (1984) 397-412 0 North-Holland Publishing Company ON THE DIFFERENCE OF THE DYNAMIC MOMENT OF INERTIA Sg,,,, FOR Xe AND Ba NUCLEI H. EL-SAMMAN, V. BARCI, A. GIZON. J. GIZON. L. HILDINGSSON*, D. JERRESTAM’. W. KLAMRA*, R. KOSSAKOWSKI and TH. LINDBLAD’ Insritur des Sciences NucltGre~ / I!VZP3. L:SMG‘), 53 Arenue des MurtJw, 38026 Grenoble CPdex Frunce T. BENGTSSON Deparrmenl o/‘ Marhemarical Ph)Gcs. Lund Insrirure q/’ Technolog~~. S-22007 Lund. Sweden and Cl. A. LEANDER L’NISOR, Oak Ridge Associuted L~t~icersiries, Oak Ridge. Tennessee, L’SA Received I6 December 1983 (Rev&d 27 March 1984) Abstract: The y-rays following the 1’2~“7~‘22Sn+ “C and “‘Sb + ’ *C reactions have been investigated using six NaI(Tl) detectors in a two-dimensional arrangement. The y-ray multiplicities have been measured and the dynamic moments of inertia .I’&, of ‘is~‘z2Xe and ‘*e.‘aoBa extracted from the energy-correlation spectra. The behaviour of these nuclei and the observed difference of .I(&, in Xe and Ba nuclei are interpreted in terms of high-spin collective properties. NUCLEAR REACTIONS 1’2~1’7~‘zzSn(‘ZC, X), E = 8&l I8 MeV; izsSb(‘*C, X), g = E 1 I8 MeV; measured yp-coin, y-ray multiplicity; deduced gy-energy correlation matrices. “8~‘22Xe, ‘28.130Ba deduced dynamic .16$,, moment of inertia. 1. Introduction The investigation of high-spin states in rotational nuclei can be performed by studying the discrete y-rays depopulating such levels. High-resolution Ge detectors in conjunction with e.g. BGO anti-Compton shields have recently turned out to be a very powerful tool ‘). Another method involves the study of the apparent continuum using NaI(Tl) detectors which have poorer energy-resolution but higher photopeak efficiencies. A l Permanent address: Research Institute of Physics, S 10405, Stockholm, Sweden 397