TOROIDAL QUADRUPOLE TRANSITIONS ASSOCIATED WITH COLLECTIVE ROTATIONAL-VIBRATIONAL MOTIONS OF THE NUCLEUS

In the framework of the collective model the longitudinal, transverse and toroidal multipoles corresponding to the excitations of low-lying levels in the ground-state band of several even-even nuclei are comput ed by inelastic electron scattering (e,e'). In connection with these t ransitions a new quantity, which accounts for the deviations from the Siegert theorem, is introduced in the framework of the Riemann rotatio nal model with non-vanishing vorticity. Inelastic differential cross s ections calculated at backscattering angles show the dominance of toro idal form factors over a broad range of momentum transfer.