Properties of ${}^8$Be and ${}^{12}$C deduced from the folding--potential model

Abstract

The $\alpha$--$\alpha$ differential cross sections are analyzed in the optical model using a double--folded potential. With the knowledge of this potential bound and resonance--state properties of $\alpha$--cluster states in ${}^8$Be and ${}^{12}$C as well as astrophysical S--factors of ${}^4$He($\alpha$,$\gamma$)${}^8$Be and ${}^8$Be($\alpha$,$\gamma$)${}^{12}$C are calculated. ${\Gamma }_{\gamma }$--widths and B(E2)--values are deduced.

2 pages LaTeX, 2 figures can be obtained from the authors