Systematics of reduced B(E3) transition probabilities and configurations of octupole (ΔI=3) isomers in mass A~200 region

Strong octupole correlations are observed in mass A ∼ 200 region giving rise to a number of isomeric states decaying via E3 type of transition involving Δj = Δl = 3 interacting orbitals. Particularly, the g_9/2 and j_15/2 neutron orbitals or the f_7/2 and i_13/2 proton orbitals are predicted to be involved in these enhanced E3 decays. To report the systematics of reduced B(E3) transition probabilities and configurations of isomers that decay via E3 transition and also to compare these isomers based on their structures such as even-even, even-odd, odd-even and odd-odd. The data for a total of 235 isomers is collected from the ENSDF/XUNDL Database of NNDC. The reduced B(E3) transition probabilities are evaluated and compiled using the available data on half-life and branching ratios of the isomeric states having E3 decay. In about 25 cases, the new adopted values of half-lives are obtained to get the B(E3) transition probabilities by RULER program. A systematic variation in the reduced B(E3) transition probability is discussed as a function of neutron and proton number to see the contribution/effect from the core particles. An enhancement is seen for the isomeric states involving the g_9/2 and j_15/2 neutron orbitals or the f_7/2 and i_13/2 proton orbitals. The enhanced E3 transition rates are observed in nuclei having configurations with octupole effects such as i_13/2 → f_7/2 and j_15/2 → g_9/2. The E3 transitions with i_13/2 → f_5/2 are having lowest B(E₃) (10^-4 to 10^-5 W. u.) values. (author)