Barrier Height Distributions --- the Influence of Weak Channels

The barrier distributions for the 20 Ne+ 58,60,61 Ni systems were experimentally determined. In the 58 Ni case one observes a distinct "structure" in the distribution (two peaks) which is partially damped for 60 Ni and completely smoothed out for 61 Ni. It seems that smoothing is caused by non-collective excitations of the target nuclei.