Nuclear models: excited states of 182Ta

[joe_blogs]

Hi all,

I'm doing some test prep for a Nuclear Physics course and working on a past paper. I've attached a photo of the question. The diagram is 3.19 in Krane. The course is based on Krane, and so the relevant chapter is Chp 5: Nuclear Models.

Problem description

The problem is to explain the energy level spacing for a series of nuclei based on some basic nuclear models. I can do some of them - e.g. 120Te and 178Os show the regularity and spin-parity combinations expected for rotational and vibrational nuclei respectively.

What I'm stuck on is the slightly bizarre level scheme for 182Ta. There appear to be over 40 levels under 1MeV, and I don't understand why. It's a pretty vague question, but I assume any answer should explain the character of the level scheme - i.e. it's great complexity.

My attempted solution

I know that nuclei in the 150<A<190 range are deformed and often have level schemes characterized by rotational bands, and that explanations of level schemes often build together multiple explanations. e.g. p146 in Krane, the levels of 164Er are partially explained by appealing to three rotational bands, built on a deformed ground-state and two vibrational states.

Any ideas would be appreciated.

Joe

 

[joe_blogs]

I've made some progress, which is essentially a reworking of the 164Er case.

Rotational level spacing is of the order of 10 keV, so that's the clear candidate for the levels. I feel like I need to supplement this with an explanation of why there are so many levels, however. I'm thinking of a series of excitations with finely split levels. Say, a deformed ground state with excited vibrational bands (both beta and gamma vibrations) with rotations built onto all of those. 182Ta is big enough to be deformed in the g.s., and with the limited data available I'm not sure what more there is to say.