KIPT Kharkov

Isovector l-forbidden transitions in odd-nuclei

The experimental data analysis of l-forbidden M1 transitions (l is an orbital momentum) in gamma decay of analogue resonances in odd nuclei is carried out. It is established that isovector magnetic dipole l-forbidden transitions (DT = 1) is observed in all region of odd-nuclei with Ŕ < 70. Its intensity in several cases is compared with that of allowed single particle Ě1 transitions.

It is followed up the shells closure influences on the quantity of the factor F=B(M1)theor/B(M1)exp. This factors have maximum for gamma transitions in the vicinity of nuclei with N = 20. Minimum values of F are connected with gamma transitions in nuclei near N = 8 and 28. It is followed that factors F has a dependence on energy of gamma transition in one and same analogue resonance: value F is increased with enlargement of relative energy of Ě1 transitions.

l-Forbidden M1 transitions are not identified in nuclei near N = 20 and 50. Besides this noticeable correlation is not revealed between values F and spectroscopic factors C2S for analogue resonances.