Candidates for Quadrupole-Octupole Mult-iphonon Excitations Observed in the Te Isotopes

Excited levels in the even-even isotopes $^{120-130}$Te have been investigated to 3.3 MeV using $\gamma$-ray spectroscopy following inelastic neutron scattering. Level characterisitics including spins, multipole-mixing and branching ratios, and lifetimes in the fs to ps regime have been deduced from $\gamma$-ray angular distributions, excitation functions, and Doppler-shift measurements, as well as $\gamma$-$\gamma$ coincidence measurements. This consistent sent of measurements has enabled us to examine multi-phonon excitations across the isotopic chain. In particular, the quintet of negative-parity states (1$^{-}$-5$^{- }$) arising from the coupling of the lowest quadrupole- and octupole-phonon exitations have been examined and candidates have been identified. Results from these investigations across the Te isotopic chain will be presented.