Parity doubling in Th219 and the onset of collectivity above N=126

Excited states in Th-219 have been observed for the first time in an experiment using the Mg-26+Pt-198 reaction and evaporation-residue-gated gamma-ray spectroscopy. Two structures of interlinked alternating-parity levels with simplex quantum numbers s=+/- i are observed, reminiscent of similar sequences in heavier odd-mass isotopes, but only three mass units away from the N=126 neutron closed shell. The emergence of quadrupole-octupole collectivity in this mass region and the trend for parity-doublet bands are discussed.