NEUTRON HOLE STATES IN Z=40 NUCLEI STUDIED WITH (P,D) REACTION ON 90ZR 91ZR AND 92ZR

The (p,d) reaction on Zr90, Zr91, and Zr92 was studied at a proton energy of 31 MeV. Deuteron spectra were measured with a broad-range magnetic spectrograph. The reaction on Zr90 excites strongly the ground state of Zr89 (l=4) and excited states at 0.588 MeV (l=1), 1.094 MeV (l=1), and 1.450 MeV (l=3). These states are shown to be consistent with pickup of neutrons from the 1g92, 2p12, 2p32, and 1f52 shell-model levels, respectively. On this basis definite spin-parity assignments are made to these levels. Small portions of the strength for pickup of these neutrons are also observed for higher excited states. The reaction on Zr91 excites the states corresponding to the creation of the 1g92 hole and the consequent coupling of this hole to a 2d52 neutron. All six of the expected one-particle one-hole states are observed. The Zr92 target, which was included to study the effect of this isotopic impurity in the Zr91 target, yielded data on a number of excited states in Zr91. © 1968 The American Physical Society.