Experimental K-vacancy production probabilities of nearly symmetric heavy-ion collision systems in comparison with the 2p. pi. -2psigma rotational-coupling model. [54. 4 and 90-MeV]

Measurements are reported for the impact parameter (b) dependence of K-vacancy production probabilities (P/sub K/(b)) in collisions of 54.4- and 90-MeV Ni with targets of Ni, Ge, and Rb. The shape of P/sub K/(b) is found to be qualitatively similar to that expected for the 2p..pi..-2psigma rotational-coupling mechanism, but the maximum found at large b is shifted to smaller b in comparison with the predicted adiabatic maximum. This behavior is investigated systematically by applying a simple scaling law within the 2p..pi..-2psigma rotational-coupling model on these and all published P/sub K/(b) data of nearly symmetric collision systems.