Study of 0(+) excitations in Gd-158 with the (n,n ' gamma) reaction

We have examined 158Gdwith the (n,n′γ) reaction at neutron energies up to 3.3 MeV to determine the collective character of 0+excitations revealed in previous 160Gd(p, t) reaction studies. Moderately large B(E2;0+→2+1) values are observed for transitions from some of the 0+ states lying above the pairing gap. From its excitation energy and decay properties, the 0+ excitation at 2276.7 keV is suggested as exhibiting two-phonon γγ strength. The high density of levels at similar excitation energies makes the identification of the other two-phonon states improbable.