Particle-hole and vibrational states in doubly closed subshell 96Zn from in-beam inelastic neutron and proton scattering

Through in-beam (n,n'γ) and (p,p'γ) reaction studies, we have identified 33 levels in 96Zr and, from (n,n') cross section and γ-ray angular distribution data, we have made spin-parity assignments for twenty of these levels. Recent DSAM nuclear level lifetimes were combined with electronic timing measurements in interpreting these states. The 1750 keV 2+ and 2439 keV 3+ states are suggested as the lowest neutron particle-hole multiplet, of ν(3s1/2, 2d5/2-1) type, expected from the double closed subshell picture. On the other hand, the band built on the 1582 keV 0+ shape isomer is determined to have vibrational collectivity up to the two-phonon level. Candidates for two-phonon vibrational states of quadrupole-octupole and double octupole type, associated with the ground-state structure exhibiting octupole softness, are proposed. (orig.)