ELECTRON-SCATTERING OFF CU-65 AND GA-71

Electron scattering on the fp-shell nuclei Cu-65 and Ga-71 has been in vestigated. Measurements have been performed up to a momentum transfer of 2.7 fm-1 at forward and at backward scattering angles in order to separate the transverse and longitudinal form factors of the low-lying excited states. This allowed the extraction of the transition densiti es and probabilities, which are compared to particle-core coupling cal culations: particle-vibration coupling model (PVCM) and quasiparticle- cluster vibration model (QCVM). These models appear to be more applica ble to Cu-65 than to Ga-71. Reasons for this are discussed. In general the transition charge densities confirm the distinction between quasi particle states and collective excitations, that one expects already o n the basis of spectroscopic factors. The relative importance of quasi particle and phonon contributions to the transitions is reflected in t he specific shapes of the transition densities for each level. Transit ion current densities are often less well predicted than charge densit ies and are quite sensitive to the model used.