Chen, Fang-QiLiu, Yan-XinSun, YangWalker, Philip MDracoulis, George2015-12-100556-2813http://hdl.handle.net/1885/58724The anomalously fast decay of a 19/2 + three-quasiparticle isomer in 171Tm was interpreted recently as an example of K mixing induced by a very small mixing matrix element but a (random) close proximity to a collective state. To understand the source of the residual interaction we have generalized the projected shell model by introducing two-body octupole and hexadecupole forces into the Hamiltonian and expanding the model space with inclusion of specific three-quasiparticle configurations. It is found that the K mixing is built up from small interactions transferred through numerous highly excited configurations that contain high-j orbitals. While the chance near-degeneracy enhances the transition strength, the octupole correlation and Coriolis coupling produce the mixing matrix element.Author/s retain copyright201210.1103/PhysRevC.85.0243242015-12-10