Population and decay of a Kπ=8– two-quasineutron isomer in Pu244

The decay of a K-pi = 8(-) isomer in Pu-244 and the collective band structures populating the isomer were studied using deep inelastic excitations with Ti-47 and Pb-208 beams, respectively. Precise measurements of M1/E2 branching ratios in the band confirm a 9/2(-)[734](nu)circle times 7/2(+)[624](nu) configuration assignment for the isomer, validating the systematics of K-pi = 8(-), two-quasineutron isomers observed in even-Z, N = 150 isotones. These isomers around the deformed shell gap at N = 152 provide critical benchmarks for theoretical predictions of single-particle energies in this gateway region to superheavy nuclei.