Resonances and fluctuations in the 16O + 15N and 12C + 19F collisions

The search and study of quasi-molecular resonances in the ³¹P composite system populated via two entrance channels are performed with two different experimental techniques. The ¹⁶O + ¹⁵N reaction products have been studied by the γ-ray detection method at cm. energies ranging from 15.5 MeV to 36.1 MeV. Binary channels of the ¹⁶O + ¹⁵N and ¹²C + ¹⁹F collisions have been studied by using the kinematical coincidence method at 26 incident energies ranging from E_c.m. = 20.6MeV to 33.5MeV for the first system, and at energies corresponding to the same excitation energies of the composite system for the second system. The ¹⁶O + ¹⁵N reaction exhibits two prominent gross structures in the large angle elastic scattering excitation function correlated with the resonant structures observed in inelastic channel γ-ray yield measurements. Spin assignments were tentatively made for the two resonances. On the contrary, no such structures can be clearly established in the ¹²C + ¹⁹F system where only indications of non-correlated structures in various channels have been observed.