Nuclear resonance fluorescence inNd142

The resonant scattering of electron bremsstrahlung by an enriched sample of ${}_{}{}^{142}{}_{}{}^{}\mathrm{Nd}$ has been studied for photon energies of up to 5 MeV. It provides estimates of the radiative widths for 13 levels. Based on the relative yields at scattering angles of 96° and 126°, unambiguous spin assignments were made to 6 of these levels. Where feasible, the yield measurements were supplemented by self-absorption data and by linear polarization studies. For the strongest excitation, at 3.425 MeV, the resonance fluorescence experiments led to its identification as a $1^{-}$ state with a radiative width ${\Gamma }_0=370\mathrm{}\pm 45$ MeV. The corresponding $E1\mathrm{}$ strength is comparable to the $E1\mathrm{}$ strengths measured in other even-even $N=82\mathrm{}$ nuclei for the $1^{-}$ member of the quintuplet arising from the coupling of the lowest octupole vibration to the $2_1^{+}$ level. The sum of the excitation energies of the $2_1^{+}$ state and the $3_1^{-}$ state in ${}_{}{}^{142}{}_{}{}^{}\mathrm{Nd}$ is consistent with such an interpretation of the 3.425-MeV level.