Transition Probabilities of the 9/2⁺ → 7/2⁺ Transitions in Odd-mass Ag Isotopes

Abstract

Conversion electrons from the 9/2+ → 7/2+ transitions in the odd-mass 105,107,111Ag nuclei have been studied in the radioactive decays of 105Cd, 107Cd and 111Pd, respectively. E2/M1 ratios have been deduced for these transitions and the half-lives of corresponding levels in 105,111Ag have been measured by means of the delayed coincidence technique. The reduced E2 transitions probabilities are compared with theoretical predictions.

Absolute transition probabilities from the 53.2 keV level in105Ag

“…The resulting halflife of the 53.2keV level in ~~ is T~(53.2keV, 9/2+)=2.33 +_0.08ns. In an earlier measurement by L.-G. Svensson et al [4] a halflife of 1.8+0.2ns was found, which is not in full agreement with the present value. A technique similar to ours was used in these measurements but instead of the high ~'-rays that was gated on in the present measurements they made use of the X-rays following the EC-decay.…”

“…Furthermore, the E2 transition probabilities between the low lying positive parity states have experimentally been found to be more enhanced than expected from shell model calculations [2]. The low lying 7/2 + state, the so called "anomalous" coupling state, has aroused much interest and been the subject of many experimental [3,4] and theoretical [2,[5][6][7][8] investigations. Theoretical calculations [2] of a three hole cluster coupled to a vibrator have for the Ag isotopes been very successful.…”

Structure of the neutron mid-shell nuclei Ag64,66111,113

“…Indeed, the j−1 anomaly, observed in the low-energy part of Ag spectra, is often interpreted as arising from three-hole clusters [2] -a direct derivative from the Shell model [3]. Within that approach, however, the M 1 transitions between members of the same multiplet are forbidden [4] which, to certain extent, coincides with the experimental observation [5]. Detailed shell model calculations [6], however, seem to fail in describing those states.…”