Inelastic electron scattering from 9Be

The electromagnetic form factors have been measured for the lowest two T = (3/2) states in 9Be at 14.393 and 16.976 MeV, the positive-parity state at 17.490 MeV, and a level of previously unknown J/sup π/ at 16.671 MeV. The range of effective momentum transfer is 0.9< or =q/sub e/< or =2.5 fm-1. The data for the T = (3/2) states show considerable deviation from the results of intermediate-coupling shell-model calculations. In particular, for q/sub e/< or =1.5 fm-1, where the M1 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