HIGH-K BAND STRUCTURES IN ER-164

Several of the known rotational bands in Er-164 are extended considera bly (to around 35 (h) over bar). In addition, a new coupled band is es tablished and found to decay by an isomeric transition with t(1/2) gre ater than or equal to 170 nsec, to the 11(-) state of the known K-pi = 7-two-quasi-proton band. The new band is interpreted as a four-quasi- particle structure, with measured values of B(M1)/B(E2) consistent wit h the configuration [7(-)] x nu i(13/2)[642 5/2(+)] x nu h(9/2)[523 5/ 2(-)], i.e. [7(-)] x [AE,AF]. This is supported by the observation of a crossing which resembles the second i(13/2) neutron crossing, BC, as sociated with the two-quasi-neutron band built on the configuration, [ AE,AF]. The routhian of the new band is close to the sum of the indivi dual routhians of [AE,AF] and [7(-)]. The cause of a small gain in ene rgy of 130-272 keV is discussed.