Properties of low-energy dipole states in232 Th have been investigated with the nuclear resonance fluorescence technique. The present work used mono-energetic γ-ray beams at energies of 2 -4 MeV from the high-intensity γ-ray source at Triangle Universities Nuclear Laboratory. Over 40 transitions corresponding to deexcitation to the ground state and first excited state were observed for the first time. Excitation energies, integrated cross sections, decay widths, branching ratios, and transition strengths for those states in 232 Th were determined and compared with quasi-particle random phase approximation calculations. Large number of E1 transitions were observed for the first time in actinide nuclei with summed strength of 3.28(69)×10−3 e 2 fm 2 . The observed summed M 1 strength of 4.26(63) µ 2 N is in good agreement with the other actinides and with the systematics of the scissors mode in deformed rare-earth nuclei.

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