Critical remarks on a scaling law for inner-shell ionization

In superheavy quasimolecules the number of created 1sσ-vacancies per collisionsP _1sσ can be evaluated approximately by a simple scaling law. This analytical relation correctly reproduces the measured dependence ofP _1sσ on the impact parameter, bombarding energy and combined nuclear chargeZ=Z ₁+Z ₂. It is emphasized, however, that the absolute ionization magnitude is underestimated typically by a factor of four. This discrepancy has been successfully resolved by the inclusion of multi-step excitation processes. It is shown that the derivation of the normalization constant in a scaling law previously reported by Armbruster's group is incorrect in the framework of first order perturbation theory.