Excited states in the N'4 nucleus have been observed by measuring the difterential scattering and reaction cross sections of C" (dd)C", C"(d,PO)C", and C~(d, p, )C"~for deuteron bombarding energies from 0.5 to 2.0 Mev. Resonances frere investigated at deuteron bombarding energies of 0.92, 1.19, 1.31, 1. 446, and 1.79 Mev, corresponding to excited states at 11. 05, 11. 29, 11. 39, 11. 503, and 11. 80 Mev in N'. Scattering matrix analysis of the elastically scattered deuterons and of angular distributions of the reaction protons to the ground state of C" gave assignments of 1+, 2, 1+, 3+, and 1+ for these states. The analysis of the C's(d, pa)C" angular distributions at 0.92, 1.19, and 1.31 Mev indicated a reaction mechanism in which the relative proton-neutron spin orientation of the deuteron is preserved.

C 13 («,a)C 13 cross sections at center-of-mass angles 54.7°, 107.9°, 142.6°, and 169.6° and C 13 (a,#)0 16 cross sections at 0° have been measured at a-particle energies from 2 to 3.5 MeV. From dispersion-theory analysis, a consistent set of J* and partial-width values has been obtained for eleven states of the compound nucleus O 17 with excitation energies between 8 and 9 MeV. I. INTRODUCTIONT HE C 13 (a,w)0 16 reaction has been extensively investigated 1-5 at a-particle bombarding energies below 5 MeV. Resonances from sharp energy states of the compound nucleus O 17 are observed. We have measured 6 the C 13 (a,a)C 13 differential elastic-scattering cross sections for a-particle bombarding energies from 2.0 to 3.5 MeV at center-of-mass angles 54.7, 107.9,142.6, and 169.6°. C ls (a,n)O u differential reaction cross sections at 0° were measured simultaneously. Elastic-scattering and reaction data were analyzed to determine the J T and the a-particle and neutron partial widths of the states of O 17 corresponding to the observed resonances.The range 2 to 3.5 MeV of a-particle bombarding energies corresponds to the range 7.9 to 9 MeV of excitation energies in the compound nucleus O 17 . Values of / and of neutron and a-particle partial widths for many of the states at these excitation energies were known from C 13 (a,w)0 16 differential cross sections 2-5 and from total cross sections of O 16 for neutrons. 2 -5 » 7 From interference terms in C 13 (a,w)0 16 angular distributions, 4 -5 relative parities of a number of states were known. To determine parities and to make complete determinations of J and partial-width values, C 13 -(a,a)C 13 and O u (n y n)O u elastic-scattering experiments are necessary. The parameters of two states at the low end of the energy interval have recently been determined from analysis of 0 16 (^,w)0 16 angular distributions. 8

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An experimental technique in which radioactive Li 8 atoms are introduced into the gas of a cloud chamber has been used to determine the energy distribution of the alpha-particles from the Li 8 breakup. The maximum of the distribution occurs at 3.3 Mev and the width of halfintensity is 1.2 ±0.2 Mev. The theoretical distribution NadEa »tPaj(Q~ 2E«)*/(J2 0 -2E a )*+lr*yE a with EQ -3A Mev, r = 0.8 Mev, and .7 = 4, gives good agreement with experimental data. N a is the relative number of alpha-particle pairs, E a is the energy of one alpha-particle, P a j is the penetrability of one alpha-particle from a Be 8 nucleus having / units of total angular momentum, and JSo and r are, respectively, the mean energy and width at half-intensity of the excited level in Be 8 . No evidence was found for a short-range group of alpha-particles which would correspond to the disintegration energy of the ground state of Be 8 .