Level structure of ¹⁰¹Rh from the decay of 8.5 h ¹⁰¹Pd

Abstract

The level structure of ¹⁰¹Rh has been investigated from the decay of 8.5 h ¹⁰¹Pd. Singles γ-ray energy and intensity measurements were taken with a 25 cm³ high-resolution Ge(Li) detector in an anti-Compton arrangement which employed a large Nal(TI) annular detector. Extensive γγ coincidence measurements were made with a Ge(Li)-Ge(Li) and a NaI-Ge(Li) arrangement with the Ge(Li) detector under Compton suppression. Triple γγγ coincidence measurements were taken in a NaI-Ge(Li)-NaI arrangement with the Ge(Li) detector under Compton suppression. The low-energy γ-rays and X-rays were studied with a high-resolution Si(Li) X-ray spectrometer. Conversion electron measurements were made with Si(Li) detectors and α_K values were determined for the most intense transitions. From these data it was concluded that levels at 157.32, 181.78, 305.3, 355.14, 478.00, 747.67, 905.61, 974.7, 978.42, 1035.5, 1057.7, 1320.4, 1359.31, 1470.82, 1696.27, 1789.26, 1820.22 and 1911.23 keV are populated in the decay of 8.5 h ¹⁰¹Pd. From log ft and α_K values determined in this work and from γ-ray intensity information definite J^π assignments were made to a number of levels and limits for the J^π values were placed for the rest of the levels in ¹⁰¹Rh. The fraction of decay of the 4.5 d isomeric state by an isomeric transition was measured to be 0.072±0.004. The level structure and the level trends in the ^{99, 101,103, 105}Rh isotopes are examined and discussed in relation to recently published results on calculated levels in these isotopes on the basis of an extended pairing-plusquadrupole model for the nucleus.