Problem of l-forbidden magnetic dipole transitions in odd nuclei

The present status of the problem of l-forbidden magnetic diopole transitions in nuclei is reviewed. The available experimental data are systematized in three regions of mass numbers, 27--49, 105--151, and 193--211, and theoretical approaches to the solution of the problem are discussed. A method for calculating the reduced probabilities of l-forbidden M1 transitions in the framework of the theory of finite Fermi systems is proposed.