STRUCTURE OF EXCITED BANDS IN TM-162 AND RESIDUAL INTERACTIONS

The nucleus Tm-162 has been populated by the Te-130(Cl-57,5n) reaction , and the gamma-cascades detected with the NORDBALL array. Eight coupl ed rotational bands involving the proton orbitals, g(7/2) [404] 7/2(+) , d(3/2)[411]1/2(+), d(5/2)[402]5/2(+), h(11/2)[523]7/2(-) and h(9/2)[ 541]1/2(-) and neutron orbitals i(13/2)[642]5/2(+), h(9/2)[523]5/2(-) and f(7/2)[521]3/2(-) have been established in Tm-162, to spins varyin g from 18 to 47 (h) over bar. Various phenomena which can be related t o residual neutron-proton interactions are discussed. In particular, s ignature inversion in the pi[541]1/2(-) x nu[642]5/2(+) bands based on the h(9/2) quasiproton and i(13/2) quasineutron, respectively, may be explained by a fairly large p-n interaction. In addition, interaction s at the crossings of bands with constituent quasiparticles differing both in parity and signature have been extracted with strength of the order of a few (4-12) keV. Such interactions also require terms beyond the standard mean field description. (C) 1998 Elsevier Science B.V.