The effect of deformation on the twist mode

Using C-12 as an example of a strongly deformed nucleus we calculate the st rengths and energies in the asymptotic (oblate) deformed limit for the isov ector twist mode operator [rY(1)(l) over right arrow](lambda =2)t(+) where (l) over right arrow is the orbital angular momentum. Whereas in a DeltaN = 0 Nilsson model the summed strength is independent of the relative P-3/2 a nd P-1/2 occupancy when we allow for different frequencies wi in the x, y, and z directions there is an enhancement of this strength due to deformatio n that is stronger than for the ordinary dipole mode but much weaker than f or the scissors mode. At the same time, it is observed that there are consi derable changes in the spectrum and that the strength is strongly fragmente d amongst these disparate levels.