Single-nucleon transfer reactions to 100Ru

Proton stripping and neutron pickup reactions have been studied to the levels of ¹⁰⁰Ru, a nucleus with collective properties that have been thoroughly studied. The neutron pickup results are consistent with a calculation for the neutron-hole structure of the J^π = 2⁺ phonon state. The proton stripping results show no resemblance to either the phonon structure calculation or to the prediction of a shell model with good seniority. Strong proton excitation of the known 8⁺ state at 3.06 MeV shows that this is not the four-boson state predicted by the ⊙IBA at that excitation.