Effect of two RPA phonons on the spectrum of the low-lying magnetic dipole transitions in deformed nuclei

The spectrum of the low-lying magnetic dipole excitations known as scissors mode is computed for several deformed nuclei by diagonalizing a Hamiltonian of separable form in a space spanned by one and two microscopic phonon states. The phonons are computed in the random-phase approximation. The effect of the coupling between one and two phonon states on the fragmentation of the M1 strength is analysed.