Strongly coupled bands as “effectively” decoupled bands
We present experimental evidence which suggests that almost all the strongly coupled bands in the rare-earth region may also be treated as “effectively” decoupled bands. In contrast to the usual decoupled bands, the strongly coupled bands seem to arise from a system where a particle carrying an “effective” angular momentumj′ is aligned to an even-even core having an “effective” rotational angular momentumR′ which is not necessarily zero for the band head but may even haveR′=2 or, 4 or, 6⋯etc. We attempt to explain these observations in a simple physical picture whereinJR, the projection ofj, the particle angular momentum, on the rotation axis, is taken as the effectively aligned spin of the last particle. Preliminary results from schematic bandmixing calculations forh9/2 andf5/2 orbitals with the Fermi energy lying near the highK single particle levels indeed reveal the existence of “effectively” decoupled bands which seem to agree with this physical picture.