MICROSCOPIC STUDY OF ALPHA+ALPHA BREMSSTRAHLUNG WITH RESONATING-GROUP WAVE-FUNCTIONS

Bremsstrahlung double cross sections for alpha + alpha collisions are computed with the wave functions obtained by using a single-configuration resonating-group method (RGM). With no adjustable parameters, the calculated values are shown to agree well with experiment. For reliable results, it is found that the intercluster interaction must yield a good fit to the empirical phase shifts in the energy region where relatively sharp resonance states exist. A simplified procedure (A-RGM), in which the antisymmetrization of the wave function is only approximately taken into account, has also been adopted to consider the bremsstrahlung problem. Comparisons between RGM and A-RGM results yield the useful conclusion that fitting empirical phase shifts alone is not a sufficient criterion to ensure accuracy in the bremsstrahlung cross sections and a proper description of the nuclear system in the region of strong cluster overlap is also important.