Dipole excitations the odd-mass nucleus 123Sb

Investigations of dipole strength distributions in heavy even-even nuclei give us valuable information about multiphonon structures of nuclei. The firm assignment of a multiphonon structure to the vibrational states of nuclei is on of the fundamental problem of nuclear physics. Comprehensive results was taken mainly by nuclear resonance fluorescence experiments in even-even nuclei. On the other hand, corresponding experiments on the neighboring odd-mass isotopes provided surprising results. Early was shown that the coupling of an additional neutron to the two phonon excitation in 142 Nd leads to 2+ direct X 3- direct X particle multiplet 143Nd, which could be observed experimentally. However in the nuclei 139La and 141Pr, differing by one proton from the N=82 neighboring isotopes (138Ba and 140Ce , respectively), only about 40 % of the expected dipole strengths could be observed in nuclear resonance fluorescence experiments. Therefore in present work we have studied dipole strength distribution in odd-mass nucleus 123Sb. Using well known nuclear resonant scattering γ-rays from Fe(n, γ)-reaction we studied 7632 keV level of 123Sb. Using recent developments of modern nuclear spectroscopy we determined next level quantum characteristics and 123 transition strengths of γ-decay in 123Sb. The enhanced E1 -transitions have been observed at energy of 5532 keV. From this we can concluded that (7/2)- state from odd-mass nuclei 123Sb is coupling all 3/2 and 5/2 states from nuclear bands