Shape coexistence in 180Hg studied through the β decay of 180Tl

The beta(+)/EC decay of (180)Tl and excited states in the daughter nucleus (180)Hg have been investigated at the CERN On-Line Isotope Mass Separator (ISOLDE) facility. Many new low-lying energy levels were observed in (180)Hg, of which the most significant are the 0(2)(+) at 419.6 keV and the 2(2)(+) at 601.3 keV. The former is the bandhead of an excited band in (180)Hg assumed originally to be of prolate nature. From the beta feeding to the different states in (180)Hg, the ground-state spin of (180)Tl was deduced to be (4(-),5(-)).