Transition quadrupole moments in superdeformed bands

Abstract

We propose a method to select core and cluster in a binary component description of atomic nuclei. The choice is based on the mismatch between measured binding energies and the underlying trend supplied by the liquid drop model. A key point is that the charge to mass ratios of parent, core, and cluster should be as nearly equal as possible. This approach reinforces our earlier conclusions concerning the occurrence of exotic clustering in actinide nuclei and also reveals a competing binary mode in these nuclei in which the cluster charge and mass are substantially larger than those corresponding to an exotic decomposition. In fact, this additional mode corresponds to superdeformation, and we predict that it should be widespread across the Periodic Table. In binary models, the transition quadrupole moments Qt of superdeformed (SD) bands depend strongly on the charge and mass splits, but are rather insensitive to other details. Indeed, given the cluster charge 〈Z2〉, Qt can be determined algebraically. We compare calculations of transition quadrupole moments with the measured values for the 41 SD bands in 21 even-even nuclei for which experimental data are available. The mass range is from A∼60 to A∼240 and the values of Qt vary from ∼3 to ∼30 e b. A good level of agreement is obtained.