β decay of the πf_{5/2} ground state of ^{77}Cu studied with 225 MeV and 0.2 MeV purified radioactive beams

Isobarically purified beams of Cu-77 with energies of 225 and 0.2 MeV were used at the Holifield Radioactive Ion Beam Facility of Oak Ridge National Laboratory to study beta decay into states in Zn-77. Data taken at 225 MeV allowed the determination of absolute branching ratios relative to the decay of Cu-77 for this beta decay as well as its daughters. From these we obtained a refined beta-delayed neutron emission probability of 30.3(22)% and a probability that the decay proceeds through Zn-77(g) of 49.1(26)%. A total of 64 gamma rays were placed in a level scheme for Zn-77 containing 35 excited states including one state above the neutron separation energy, whereas two gamma rays were observed for the beta n branch to states in Zn-76. The growth and decay curves of some prominent gamma rays indicate a single beta-decaying state with a half-life of 480(9) ms. The decay pattern for Cu-77, with observed feeding of 8(3)% to 7/2(+) Zn-77(g) and 6(3)% to 1/2(-) Zn-77(m), in contrast to the large feeding observed for decay of pi p(3/2) Cu-73(g) to 1/2(-) Zn-73(g), strongly suggests a pi f(5/2) ground state for the studied Cu-77 activity.