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The main purpose of the present work is the investigation of the α-cluster phenomenon in 16 O. The 12 C( 6 Li,d) 16 O reaction was measured at a bombarding energy of 25.5 MeV employing the Sao Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion detection technique. Resonant states around 4α threshold were measured and an energy resolution of 15 keV allows to define states previously unresolved. The angular distributions of the absolute cross sections were determined in a range of 4-40 degree in the center of mass system. The upper limit for the resonance widths was obtained, indicating that the α cluster structure information in this region should be revised.

There exists an intriguing problem when bosonic clusters as bound states of fermions are produced in the reaction, and the Bose character of the composite clusters competes with the fermionic properties of their constituents. In the analysis of 40 Ca + 40 Ca reactions at 35MeV/A we selected classes of projectile-like sources with exit channels consisting of only bosons, only fermions, only even-even nuclei, only odd - odd nuclei, only even - odd nuclei and only alpha-conjugate nuclei, respectively and searched for kinematic characteristics of these systems which might differ depending upon the type of matter selected. The distributions of various observables for the different classes of matter and comparisons between them will be presented and discussed.

Characteristics of the decay of alpha like nuclei produced in various reactions with alpha conjugate nuclei are discussed. We observe a significant number of events in which a large fraction of the system breaks up into alpha-conjugate nuclei. Lighter fragments in the various decay channels appear to originate from a neck-like region between 4 and 7 cm/ns whereas the heavier fragments appear to originate from velocities near the beam velocity. This behavior is consistent with a hierarchy effect that cannot be explained by statistical processes.