Abstrakt
The toroidal, compression and vortical dipole strength functions in semi- magic Sn-124 (and partly in doubly magic (100),Sn-132) are analyzed within the random-phase-approximation method with the SkT6, SkI3, SLy6, SV-bas and SkM(+) Skyrme forces. The isoscalar (T = 0), isovector (T = 1) and electromagnetic ('elm') channels are considered.
Both convection j(c) and magnetization j(m) nuclear currents are taken into account. The calculations basically confirm the previous results obtained for Pb-208 with the force SLy6.
In particular, it is shown that the vortical and toroidal strengths are dominated by jc in the T = 0 channel and by jm in the T = 1 and 'elm' channels. The compression strength is always determined by j(c).
It is also shown that the 'elm' strength (relevant for the (e,e') reaction) is very similar to the T = 1 one. The toroidal mode resides in the region of the pygmy resonance.
So, perhaps, this region embraces both irrotational (pygmy) and vortical (toroidal) flows.