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Angular distributions for 16 0(-i, 3 He) 15 N and 40 Ca(d, 3 He) 39 K reactions were measured at an energy of 34.4 MeV. The applicability of the distorted-wave theory to these reactions and the ability to extract reliable spectroscopic factors was investigated. Calculations using the local zero-range, nonlocal, and finite-range formulations are compared with the data. The roles of L-S coupling, deuteron optical-model parameters, and radial cutoffs on the predicted shape and magnitude are presented. The local zero-range and finite-range forms of the theory give comparable spectroscopic factors, while the nonlocal calculations are consistently low. Deviations from the closed-shell description of the ground states of 16 0 and 40 Ca are observed. Substantially all the lp hole strength in 16 0 is found, and in 40 Ca some deeper 1 -2 hole strength is seen. Results of 40 Ca(i,/) 39 Ca reactions are also presented.

An investigation of the proton ground-state configurations in the even zirconium isotopes (A = 90, 92, 94, 96) was undertaken using the (d, 3 He) reaction at a deuteron energy of 34.4 MeV. The experimental angular distributions were compared with distorted-wave calculations in the finite-range approximation which include nonlocality in the distorted waves. The residual yttrium isotopes (A =89, 91, 93, 95) have £~* ground states, and the observed spectra can be interpreted in terms of a simple shell-model picture which considers hole and particle configurations in the lg 9 /2, 2pi/2, 2p 3/2 , and l/ 5 / 2 proton shells and allowed couplings in the 2^5/2 neutron shell. It was found that the filling of the 2d 5 /2 neutron shell apparently has a measurable effect on the relative amounts of the (2^i /2 ) 2 and (lgg/ 2 ) 2 proton admixtures in the zirconium ground states. The strength of the (2^i/ 2 ) 2 term in the ground-state wave functions was determined to be: 64% for 90 Zr, 55% for 92 Zr, 66% for ^Zr, and 86% for 96 Zr.

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DISCUSSIONThe experiments described in the preceding section have demonstrated that, with Ge(Li) detectors, the resonant scattering of bremsstrahlung can be successfully applied to the heaviest stable nuclei. In these nuclei, any level in the range of 1.5 to 4.5 MeV excitation energy can be observed with this method, providedj^ r 0 2 /r ^ 5 meV, where A is the abundance of the isotope in the scatterer. This means that for g= A = ro/F= 1, all levels having lifetimes shorter than ^lO -13 sec can be studied without regard to the multipole character.As far as the nucleus Bi 209 is concerned, resonant scattering from the §+ and J^-+ members of the 2.6-MeV septuplet has been observed. From the summary given in Table II it is concluded that the measured El strengths to the ground state are well reproduced by the particle-vibration coupling model in the form used by Hamamoto, 10 with an effective charge e eif 2 (El) =0.05. Nuclear-Structure Studies of 91.92,93,95,97]^ and 94The structure of the low-lying levels of 91,92,93,95,97^ and 94 Mo was investigated with the proton-stripping ( 3 He, d) reaction on targets of 9o,9i,92,94,96 Zr an d 93Nb. The incident energy was 30.9 MeV for the 91 -92 Zr and 93 Nb reactions and 24.7 MeV for the 94 > 96 Zr reactions. The 90 Zr reaction was studied at both energies. The experimental angular distributions are compared with local zero-range distorted-wave Born-approximation calculations, and spin, parity, and spectroscopic factors are deduced. The extracted spectroscopic factors are used to establish the proton configurations of the target ground states. The observed levels and spectroscopic factors are compared with shell-model predictions based on an 88 Sr core. A surprising deviation from results of the simple shell-model calculations is observed for the relative transfer strengths to the two lowest 2+ levels in 94 Mo.