  Spectroscopic factors in 10Be, 11Be and 12Be, extracted from (d,p), one
neutron knockout, and (p,d) reactions are interpreted within the rotational
model. Assuming that the ground state and first excited state of 11Be can be
associated with the 1/2[220] and 1/2[101] Nilsson levels, the strong coupling
limit gives simple expressions that relate the amplitudes of these
wavefunctions (in the spherical basis) with the measured cross-sections and
derived spectroscopic factors. We obtain good agreement with both the measured
magnetic moment of the ground state in 11Be and the reaction data.
