Low-lying Collective States in Ba-136

Low-lying collective states in Ba-136 were investigated with (n,n'gamma) techniques, including Doppler-shift attenuation lifetime measurements. The level spins, lifetimes, branching ratios, multipole-mixing ratios and transition strengths reveal candidates for symmetric-phonon states up to third order. The 2(ms)(+) mixed-symmetry state was confirmed as unfragmented and a candidate for a [2(1)(+) circle times 2(ms)(+)](3+) two-phonon mixed-symmetry state is proposed.