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the observed average final energies. On the basis of these initial conditions we further calculated by the method of Boneh, Fraenkel, and Nebenzahl 5 the average energy of the 5 He at the time of its decay taking into consideration its exponential decay with a half-life of 8 xlO" 22 sec. This curve is also shown in Fig. 3. The measured average energy of the 5 He at the time of breakup (6.3 ±0.8 MeV) yields a unique graphical solution to the initial conditions, i.e., E F (0) = 40 ±11 MeV and £ 5 (0) = 3.9±0.9 MeV. This solution applies only to neutrons which are coincident with a particles above 9 MeV. An approximate correction for the missing events gives E F (0) = 31 ± 11 MeV and £ 5 (0) = 3.2 ±0.9 MeV.The average initial conditions obtained here for the emission of 5 He are similar to those obtained in Ref. 5 from trajectory calculations which were used to reproduce the properties of the longrange a particles in spontaneous fission of 252 Cf and in particular their angular distribution relative to the fragments. Our results are also in good agreement with a similar trajectory calculation performed by Musgrove 6 who fitted his calculation to the experimental angular distribution of Raisbeck and Thomas 7 which is narrower than the experimental angular distribution 8 used by Boneh, Fraenkel, and Nabenzahl. Rajagopalan and Thomas 9 recently remeasured this angular distribution and found it to be in substantial agreement with the results of Raisbeck and Thomas. 10 We have also performed trajectory calculations in which E F (0) is a Gaussian distribution with cr = 12 MeV and a mean E F (0) = 28 MeV,The investigation of four-particle configurations in nuclei has recently been extended from nuclei of the sd shell into the Ni region 1 " 3 via the ( le O, 12 C) reaction. However, extraction of reliable spectroscopic information is difficult because of the strong Q -value dependence of the cross section 4 and the uncertainties in knowing E 5 (0) has a Maxwellian distribution with E s (0) = 3.0 MeV, and the initial emission of the 5 He is isotropic between 30° and 150° with respect to the fragment direction. The calculated a spectrum (which takes into account the lifetime of 5 He and the backward recoil of the a in the 5 He decay) is shown in Fig. 2 to be in good agreement with the experimental results. 9) also made trajectory calculations to fit their experimental results. They state (Ref. 9) that their results are in substantial agreement with the results of Musgrove (Ref. 6) despite the fact that they obtain a much lower fragment kinetic energy at scission (7.5 MeV versus 25 MeV of Ref. 6).the various configurations of the transferred fournucleon cluster. 5 A more attractive approach is the ( 6 Li,d) reaction which extensive studies 6 " 7 on light nuclei have shown to be a good a -transfer reaction. Furthermore, distorted-wave Bornapproximation (DWBA) calculations 7 indicate that the Q-value dependence of the cross section is ( 6 Li, tf)on 58 Niand 64 NiThe ( 6 Li,d) reaction has been performed on 58 Ni and 64 Ni at 38 ...

The 'Pb(p, o)' Tl reaction has been studied at E~= 35 MeV. Excitation energies and angular distributions have been obtained for many new states in . 'Tl. Cluster model distorted-wave Born approximation calculations are shown to produce excellent fits to the angular distributions. Among the new states, four are given (15/2, 17/2)+ assignments and one is assigned as (19/2, 21/2)+ on the basis of the distorted-wave Born approximation fits. NU/LEAg REACTIONS Pb(ps ot)$ Ep =35 MeV; measured o (8); T]. deduced levels; enriched target, DWBA analysis; compared with weak coupling model.

The ( 6 Li, d) reaction, though rather extensively applied to the study of light nuclei, 1 has scarcely been used 2 * 3 for target nuclei with A ^ 40. Its cross section was believed to be very small in this mass region, and the ( 16 0, 12 C) reaction has been mainly used instead for a-transfer studies. 4 * 5 Increased interest in such studies has been prompted by the experimental results of the ( 16 0, 12 C) reaction on Ca and Ni isotopes and by the interpretation of these results in terms of quartet structures. 5 In spite of its reported weakness, the ( 6 Li, d) reaction exhibits important advantages over the ( 16 0, 12 C) reaction which make it highly desirable to extend ( 6 Li, d) measurements to heavier nuclei. (i) Better energy resolution can be obtained because of the smaller energy loss of Li ions in the target, (ii) More clearly structured and hence more conclusive angular distributions are expected at energies easily obtained with tandem accelerators (Coulomb-barrier heights, E lab~1 5 MeV for Li + Ca and 40 MeV for O + Ca). (iii) The strongly developed a-d cluster structure 6 of 6 Li favors or transfer and justifies, at least as a first attempt, the utilization of an a-stripping distorted-wave Born approximation (DWBA) (which can be performed in zero-range approx--imation because of the s state of mutual a-d cluster motion). The parentage for 16 O-0? + 12 C(g.s.) is weak, 7 " 9 and the comparably strong 16 0-o?+ 12 C(4.4 MeV) component impairs 10 * 11 the usefulness of the ( 16 0, 12 C) reaction for studies of ^-particle transfer.In the present study for the first time angular distributions for the reaction 40 Ca( 6 Li, ^) 44 Ti are presented and discussed. This reaction is of special interest, 44 Ti with four nucleons outside a doubly closed shell being the fp-shell analog of 20 Ne, for which well-developed features of the a -like correlations are found.The experiment was concurrently begun at Argonne 12 and at Rochester, and was finished at a Transfer to 44 Ti by the ( 6 Li, d) ReactionThe reaction 40 Ca( 6 LM) has been studied at £( 6 Li) =32 MeV. Clearly structured angular distributions, with maximum cross sections of the same order of magnitude as those reported for the reaction 40 Ca( 16 O, 12 C), are obtained. They are well described by atransfer distorted-wave Born-approximation calculations. 735