LOW-LYING MAGNETIC DIPOLE EXCITATIONS IN ACTINIDE NUCLEI

The M1 excitation of K=1+ states in Th232 and U238 through inelastic electron scattering is studied within a quasiparticle random-phase-approximation approach with quadrupole-quadrupole, spin-spin, and rotational-vibrational interactions. The calculated distorted-wave Born approximation (e,e) form factors and the low-energy spectrum of 1+ states are in good agreement with the experimental data. The strongest experimentally observed 1+ states can be interpreted as isovector rotational vibrations, in which several quasiparticle pairs perform a scissors type of vibrational motion. © 1990 The American Physical Society.