Anomalous band-crossings in the N=57 isotones ¹⁰³Pd and ¹⁰⁵Cd

Abstract

High-spin states of the N=57 isotones, 103Pd and 105Cd, have been studied using the reactions 94Zr( 16O, alpha 3n)103Pd and 94Zr( 16O,5n)105Cd. The nu h11/2 yrast bands in both nuclei are extended up to spin 47/2h(cross), past the first band-crossing. The observed increase in alignment in both bands is significantly lower than in analogous bands in the heavier odd-N isotopes, where the alignment is thought to be due to a pair of low- Omega h11/2 neutrons. The relatively low increase in alignment in 103Pd and 105Cd is consistent with cranked shell model calculations which predict that at low deformation both the (g9/2)2 proton and the (g7/2)2 neutron alignments are favoured in these N=57 isotones, over the (h 11/2)2 neutron alignment.