The decay of mass-separated 99g, mAg

Abstract

The decays of neutron-deficient 15 s 99Ag and 124 s 99gAg nuclides have been investigated at the Leuven Isotope Separator on-line facility. Sources were produced by the 92Mo( 14N, 2p5n) and nat Zr( 14 N, x n) reactions. Positron, conversion electron, X- and γ-ray singles spectra together with γ-γ coincidence measurements have been performed on mass-separated samples. The 1 2 − isomeric level in 99)Ag decays with a 163.6 keV isomeric transition to a 7 2 + level at 342.6 keV. Of the 106 γ-rays observed in the β + EC decay of the 99Ag ground state, 68 γ-rays (92 % of the γ-ray intensity) have been placed in a proposed level scheme. The relative variation of the J π = 9 2 + and 1 2 − levels in odd-mass Ag isotopes has been calculated using a residual proton-neutron delta interaction. The occurrence of decoupled bands in the odd Pd isotopes is discussed. Detailed calculations for 99Pd have been carried out in the framework of the Nilsson model (strong-coupling wave functions) using a strong Coriolis band mixing. Energy spectra for high-spin states, wave functions and low-lying non-yrast levels (below E x = 1 MeV) are also discussed.