Heavy-ion optical potential for sub-barrier fusion deduced from a dispersion relation

Towards a unified description of light ion fusion cross section excitation functions

“…But these as well as the smooth 12C + 16N, lOB+ 160 fission excitation functions have been equally well described by a phenomenological parametrization ofthe fusion transmission coefficients T~<'e• which encompasses the constraints due to the effective interaction in the entrance channel at low energy and to the angular momentum dependent compound nuclear level density at higher energy [8,9] Actually, the unified description of excitation functions oflight systems covering a broad energy range requires the proper consideration of the competition between direct processes and fusion for the flux absorbed from the entrance channel, in terms of ingredients from both nuclear dynamics and structure. In this sense, it has been shown phenomenologically [8,9,[39][40][41] andjustified in the frame-work of general reaction theories [15,25,[42][43][44][45]] that the optical model description of fusionisasimple but relevant and efficient procedure. In analogy with the expression of UR [ 46] (and Te) UF and T~<'e are expressed [39] in terms of optical model wave functions and WF, the imaginary part ofthe potential which is responsible for absorption due to fusion.…”