New collective structures in the 163Yb nucleus.

The ¹⁵²Sm(¹⁶O, 5n)¹⁶³Yb reaction at a beam energy of 93 MeV was used to study the excited states of ¹⁶³Yb with the AFRODITE γ -ray spectrometer at iThemba LABS. The level scheme of ¹⁶³Yb has been extended and new rotational bands established. The band based on the ground-state has been extended from a spin of 11/2^- to spin 43/2^-. A high-K band based on the neutron [505]11/2^- Nilsson orbital has been observed and is reported for the first time in this work. Additional new states in ¹⁶³Yb were observed which all decay to the yrast band. Some of these states are placed in a sequence which is conjectured to be a γ band involving a coupling with the i_13/2[642]5/2⁺ neutron orbital. The band structures are discussed with reference to Cranked Shell Model (CSM) calculations and a systematic comparison with the neighbouring nuclei. [ABSTRACT FROM AUTHOR]