NEW INSIGHTS INTO THE NUCLEAR STRUCTURE IN NEUTRON-RICH ~(112,114,115,116,117,118)Pd

摘要

By means of γ-γ-γ and γ-γ(θ) measurements of prompt fission y rays from ~(252)Cf using the Gammasphere, weakly populated odd-parity doublet bands were identified and extended in ~(112,114,116)Pd, and interpreted as disturbed chiral structure. Evolution from chiral symmetry breaking in ~(110,112)Ru with maximum triaxiality to disturbed chirality in ~(112,114,116)Pd is proposed. Based on the analysis of the signature splittings of the y bands in the even-N Pd isotopes, onset of wobbling excitations was identified in ~(114)Pd, a N=68 isotone of the first even-even wobbler ~(112)Ru. The extended level schemes of the Pd isotopes, mainly in ~(114,115,118)Pd, and Total Routhian Surface (TRS) calculations allowed an interpretation for the systematics of the band-crossings in the Pd isotopes, revealing the driving effects of the (πg_(9/2))~2 and (υh_(11/2))~2 alignments and shape evolutions and coexistence in the Pd isotopes. Maximal triaxiality in Ru and Pd isotopes is reached for N=68,~(112)Ru and ~(114)Pd, 4 neutrons more than found in the theoretical calculations.