Impact parameter dependence ofL- andK-shell excitation in I-Ag collisions

Abstract

The impact parameter dependence of theL- andK-vacancy production of target and projectile was measured in I-Ag collisions at 40 MeV and 63 MeV in a X-ray particle coincidence experiment. A largeL-vacancy production is found for impact parametersb smaller than theL-shell radius with a pronounced increase forb<250fm. TheL-shell excitation is discussed in terms of 4fσ excitation and vacancy transfer in the 3pσ, 3dπ, 3dσ molecular orbitals through 3pπ-3pσ and 3dδ-3dπ-3dσ rotational-couplings. The 2pσ excitation probability is obtained from the summedK-vacancy production probability, and compared with the prediction of 2pσ excitation in a multiple collision process. The latter is determined by folding the measured IL-shell excitation probability with the impact parameter dependence of the 2pπ-2pσ rotational coupling. The discrepancy observed at small impact parameters suggests an enhanced 2pπ and 2pσ excitation at small impact parameters in a one-collision process. TheL- andK-vacancy sharing probabilities are found to be impact parameter independent over a large impact parameter range.