Electromagnetic transitions in some doubly odd deformed nuclei

Nanosecond lifetimes of excited states in doubly odd deformed nuclei have been determined by in-beam measurements applying the method of delayed γ-γ coincidences as well as by experiments in the radioactive decay with the method of delayed γ-ce coincidences, respectively. Analysing the time distributions and delayed γ-ray spectra, the half-lives of isomeric states of 160Tb, 156Ho, 158Ho, 162Ho, 164Ho, 166Ho, 162Tm, 178Ta, 186Re and 188Re could be obtained for the first time. Furthermore, upper limits for the half-lives of fifteen excited states in 160Tb, 164166Ho and 186188Re have been estimated. For eight isomeric levels in 186188Re, the lifetimes earlier determined have been remeasured. Unlike previous studies, the existence of isomeric states at 87.2 keV in 156Ho and at 179.9 keV in 162Ho is suggested. Absolute γ-ray transition probabilities are deduced and compared with single-particle estimates according to Weisskopf and Nilsson, the latter also including pairing correlations. The K-, Ω- and f-forbidden transitions can qualitatively be explained in terms of configuration mixings. Experimental E1, ΔK = 1 transition matrix elements in odd-odd deformed nuclei are supposed to be appreciably influenced by higher-order vibrational admixtures coupled via RPC and p-n interaction mixings. (Auth.)