ON TRANSITIONS BETWEEN SENIORITY-4 AND SENIORITY-2 STATES COMPARED TO 2-PHONON-ONE-PHONON TRANSITIONS

Using the generalized quasi-spin representation, sum rules are derived for the electric quadrupole transition rates connecting the first 2+ state of seniority two and states of various seniority (v = 2 → v = 4). It is shown that the sums over states of seniority four approach the vibrational sum rule for large degeneracies. In several cases, individual transitions have been calculated for a surface delta interaction. When the single-particle states are degenerate, it is shown that 0+, one 2+ and one 4+ exhaust almost entirely v = 2 → v = 4 sum rule. A calculation is also performed of these transitions in a case where the single-particle energies are no longer degenerate. Here there is some mixing between seniority-2 and -4 states, and the picture concerning transition rates is more complicated. © 1968.