Nuclear Isomerism in the N = 127 Isotones

Abstract

<p> The alpha decay properties of nuclei decaying across the N = 126 closed neutron configuration are examined. A systematic occurrence of isomerism is esteblished in the odd-odd N = 2.27 isotones from a detailed study of 214Fr and 216Ac. Energy level spacings of the odd-odd N = 125 isotones 208Bi, 210At, and 212Fr are found to exhibit a distinct· correspondence. The Mang shell model theory of alpha decay is evoked to explain the reduced width fluctuations of the even-odd N = 127 isotones. Theoretical and experimental results are also presented for the alpha decay of 215Ra. The new isotopes 222Th , 221Th , 218Ra, and . 217R a are synthesized and studied. Precise atomic masses are calculated for several nuclei from the measurement of alpha decay Q-values. </p>