Excitation functions have been measured for di6'erent fragments produced in the ' Y{' F,x)y reactions between 135 and 143.25 MeV incident energy in 250 keV steps. Cross section fluctuations correlated in atomic number and detection angle arg observed with a coherence width of 200 -500 keV. Lifetimes have been deduced and are of the order of a complete nuclear rotation. The data can be explained in terms of quasimolecular configurations and/or an orbiting situation in a dinuclear system.
The cross section for total fusion of the reaction ' 0+ ' C was studied over a large range of energies from near the Coulomb barrier B& to -6B~. Good agreement was found between the critical angular momenta deduced from the experimental results and the predictions of different models. The reaction ' 0+ ' C, leading to the same compound nucleus Si, was studied in the second fusion region (above -2B&). By comparing the relative cross sections for fusion-evaporation to each isotope it is shown that for different entrance channels, even at the highest energies studied, the reactions appear to pass by the formation of a compound nucleus. The critical angular momenta were found to be systematically different from ' 0+ ' C. This difference, which may be due partially to the entrance channel spin, is interpreted as arising from the effect of direct reactions diverting flux from the compound nuclear processes. NUCLEAR REACTIONS ' 0, ' 0, and ' 0 beams on ' C, ' C, and ' C targets, respectively; natural and enriched targets; E&,b --32 to 140MeV; time of flight with Z identification technique; fusion evaporation and direct cross section measurements from Z=5 to 14 and 3=10 to 29; statistical model calculations; entrance channel effects discussed; macroscopic model results for total fusion cross sections.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.