COEXISTENCE IN EVEN-EVEN CD NUCLEI - GLOBAL STRUCTURE AND LOCAL PERTURBATIONS

The even-even Cd nuclei near neutron number N = 66 are indicative of the presence of two rather distinct families of excitations: anharmonic quadrupole vibrations and more deformed intruder particle-hole excitations. We discuss these excitations as mainly coexisting families of states forming the global structure of these nuclei. Then, we investigate how local large perturbations can cause strong mixing between the two families. The coupling is studied in detail and a particular set of selection rules governing the mixing leads to the introduction of a new basis in order to discuss the interaction between vibrational and intruder 9 excitations. Numerical applications are carried out for Cd-112,114.