Impact-Parameter Dependence of Vacancy Production in Strongly Bound Quasimolecular States of Heavy Collision Systems

Abstract

With a new method to determine the impact-parameter dependence, P(ρ), of K-shell vacancy production, which utilizes a kinematic analysis of Doppler-broadened x-ray lines, we show that the K-shell excitation probability in heavy collision systems at Coulomb barrier energies is both large and narrowly peaked at small impact parameters. In particular, for 1sσ excitations, P(ρ≃0) can exceed a few percent with approximately half the total cross section contributed by collisions with ρ≲40 fm.