Evidence of Further Rotational Structure inAl26

Abstract

A unique spin assignment of $J=4\mathrm{}$ is obtained for the level at 2068.7 keV in ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ which previously had a spin assignment of $J=3\mathrm{}$. The level was populated with the reaction ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}\mathrm{}(p,n)\mathrm{}{}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ at a proton energy of 7.4 MeV and the angular distribution of the ground-state $\gamma$ ray determined. The excitation energy and the $E2\mathrm{}$ strengths indicate that this level and the level at 3404 keV with $J=5\mathrm{}$ are members of a $K=3\mathrm{}$ rotational band based on the $3^{+}$ level at 417 keV. This proposed band, based on the parallel coupling configuration of a particle in Nilsson orbit $5 (\Omega =\frac{5}{2})$ with a particle in orbit $9 (\Omega =\frac{1}{2})$, is evidence of further rotational structure in ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$.