Abstract
Excited states have been studied in ____iso{159}{Sm}, ____iso{161}{Sm}, ____iso{162}{Sm} (Z~=~62), ____iso{163}{Eu} (Z~=~63), and ____iso{164}{Gd} (Z~=~64), populated by isomeric decay following 238U projectile fission at RIBF, RIKEN. The isomer half-lives range from 50 ns to 2.6 ____mus. In comparison with other published data, revised interpretations are proposed for ____iso{159}{Sm} and ____iso{163}{Eu}. The first data for excited states in ____iso{161}{Sm} are presented, where a 2.6 ____mus isomer is assigned a three-quasiparticle, K^____pi = 17/2^- structure. The interpretation is supported by multi-quasiparticle Nilsson-BCS calculations, including the blocking of pairing correlations. A consistent set of reduced E1 hindrance factors is obtained. Limited evidence is also reported for isomeric decay in 163Sm, 164Eu and 165Eu.