Exotic clustering in Ra-222,Ra-224,Ra-226

We describe the J pi = 0(+), 2(+), 4(+),... ground state bands of (222,224,226) Ra, using a model in which these bands are treated as a C-14 cluster orbiting the appropriate Pb core. For each isotope, we obtain good agreement with the measured half-life for the C-14 decay of the 0(+) ground state, as well as with the excitation energies and in-band E2 decays of other states of the ground state band. We also propose extensions of the model to deal with the observed low-lying J pi = 1(-), 3(-), 5(-),... bands, their in-band E2 decays, and the E1 and E3 transitions connecting to the ground state bands. (C) Elsevier Science B.V.