Anisotropy of PbL3-subshell x rays excited by low-velocity-proton impact

Abstract
The anisotropy of the resolved Ll x-ray line emitted from proton-excited Pb atoms has been measured. The anisotropy coefficient is strongly dependent on the projectile energy within the proton energy range studied (from 0.4 to 3.0 MeV). A detailed explanation of this energy dependence is suggested in terms of the Coulomb interaction of the projectile with the target nucleus. The deflection effect is discussed in earlier publications; the retardation effect is introduced here for the first time in the context of the alignment of L3-subshell vacancies. Both effects are treated with appropriate weight functions for the different magnetic substates of the L3 subshell.