Fragmentation of low-lying dipole strength in the odd-mass nucleus 133Cs

The fragmentation of low-lying dipole strength in the odd-mass nucleus 133Cs has been investigated in nuclear resonance fluorescence (NRF) experiments performed at the bremsstrahlung beam of the Stuttgart Dynamitron accelerator at an end-point energy of 4.1 MeV. In the excitation energy range 2.3 endash 3.7 MeV in total 22 new dipole excitations were observed. From the high-resolution γ-ray spectra measured by three high-efficiency Ge detectors the reduced excitation probabilities B(E1)↑ or B(M1)↑ were deduced. The fragmentation and absolute total strengths of the detected dipole excitations are compared with results for the neighboring even-even, γ-soft nucleus 134Ba, where both, rather strong scissors mode-like M1 and two-phonon E1 excitations are known from recent NRF experiments. copyright 1997 The American Physical Society