The electromagnetic form factors have been measured for the lowest two $T=\frac{3}{2}$ states in ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$ at 14.393 and 16.976 MeV, the positive-parity state at 17.490 MeV, and a level of previously unknown $J^{\pi }$ at 16.671 MeV. The range of effective momentum transfer is $0.9\le q_e\le 2.5$ ${\mathrm{fm}}^{-1\mathrm{}}$. The data for the $T=\frac{3}{2}$ states show considerable deviation from the results of intermediate-coupling shell-model calculations. In particular, for $q_e\le 1.5$ ${\mathrm{fm}}^{-1\mathrm{}}$, where the $M1\mathrm{}$ multipole dominates, the data lie well above these calculated values. There is some evidence that the state at 16.671 MeV has positive parity. The results of single-particle shell-model and Nilsson-model calculations are compared with the data for this state. The experimental form factor for the 17.490-MeV state can be fitted with single-particle shell-model results in the $2s-1d$ space.

NUCLEAR REACTIONS ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$(e,e'), sharp states from 14 to 18 MeV; measured form factors at 160°, 140°, $0.9\le q_e\le 2.5$ ${\mathrm{fm}}^{-1\mathrm{}}$; comparison with shell-model and Nilsson-model calculations.

• Received 29 December 1982

DOI:https://doi.org/10.1103/PhysRevC.28.489