The attenuation of the intra-band intensity of a superdeformed band which results from mixing with normally deformed configurations is calculated using reaction theory. It is found that the sharp increase of the attenuation is mostly due to the tunnelling through a spin dependent barrier and not to the chaotic nature of the normally deformed states.
We derived analytic formulas of the effective astrophysical S factor, Seff, for a non- resonant reaction of charged particles using a Taylor expansion of the astrophysical S factor, S(E), and a uniform approximation. The formulas will be able to generate more accurate approximations to Seff than previous ones.
