${\left(sd\right)}^4$ states in ${}^{12,14}\mathrm{Be}$

For suggested cluster states beginning at about 10 MeV in ${}^{12}\mathrm{Be}$, absolute energy and relative energy spacings agree well with calculations for the ${}^8\mathrm{Be}\times {\left(sd\right)}^4$ configuration. Comparison indicates that the proposed $\left(8^{+}\right)$ state at 20.9 MeV is probably $6^{+}$. A similar calculation for ${}^{14}\mathrm{Be}$ predicts that the lowest ${\left(sd\right)}^2$ and ${\left(sd\right)}^4$ states are rather close together in that nucleus.

Figure 1

For $0^{+},2^{+}$, and $4^{+}$, excitation energies are plotted vs $J(J+1)$ for three sets of states: diamonds and dot-dashed line: experimental energies in ${}^{20}\text{O}$; circles and dotted line: calculated shell-model energies in ${}^{20}\text{O}$; triangles and solid line: suggested cluster states [19] in ${}^{12}\text{Be}$ after subtracting 10.3 MeV.

Figure 2

Same as in Fig. 1 but with $6^{+}$ and $8^{+}$ [15, 16] included. Also shown are $6^{+}$ and $8^{+}$ from $J=2$ core, $x\text{"}s$, and dot-dashed line.