Do Rotational Bands in Nuclei Indicate Changes in Deformation or Nucleon Levels?

[eXorikos]

A nucleus has several rotational bands built on different Nilsson Model levels. Do these bandheads occur for different deformation of the nucleus or does an individual nucleon change level?

My educated guess is that it's the deformation that changes, but I need to be sure. :)

 

[eXorikos]

I read in a paper that these rotational bands in the nucleus I'm studying are based on quasiproton excitations. So this means it's a collective excitation that behaves like a single proton.

However when I look into a different paper, I read this.
For a system with an odd number of nucleons the lowest non-collective excitations are single-quasiparticle states.

Now I'm confused.