DISTRIBUTION OF FUSION BARRIERS

Heavy ion fusion cross sections and compound nucleus average spin valu es obtained from distribution of fusion barriers are discussed. Variou s shapes of distribution functions are studied using a truncated Gauss ian distribution function (TGD). It is shown that fusion cross section and average spin values are less sensitive to different parametrizati on of TGD function, whereas the second derivative of the product of en ergy and fusion cross sections (w.r.t. energy), obtained from the corr esponding TGD functions are significantly different depending on the s hape of the barrier distribution function. It is also shown by chi(2) analysis of fusion cross section data that some systems favour a narro w Gaussian distribution function whereas others, for which the vibrati onal and rotational collective states are less important, favour a fla t barrier distribution. A physical interpretation of the dynamical pro cess that gives rise to different barrier distribution is given in the framework of microscopic coupled channel calculations.