Binding and Coulomb-deflection effects in L -shell Coulomb ionization by heavy charged particles. Low particle velocities

Experimental cross sections for L -shell ionization by heavy charged particles, of atomic number small compared to the target atomic number and with velocities low compared to the L -shell orbital velocities, can be smaller by more than an order of magnitude than the quantum-mechanical predictions in the plane-wave Born approximation (PWBA). The contribution of two effects, not contained in the PWBA, is derived. These effects are the binding of the L -shell electrons to the moving particle during collision and the Coulomb deflection of the particle in the field of the target nucleus. As developed here for L shells and previously for K shells, the theory treats the excitation of inner shells from perturbed stationary states (PSS) and incorporates the effect of the Coulomb-distorted wave of the heavy charged projectile semiclassically. It agrees well with experimental L -shell cross sections of 16 different target atoms for protons, and accounts for the isotope effect observed on various targets with protons and deuterosn of equal velocities.