Angular Distribution for Electron Excitation of the4S2→4P2Transition in ZnII: Comparison of Experiment and Theory

Differential electron-scattering cross sections for inelastic excitation of an ion have been measured for the first time. Experiments were carried out in a crossed electron-ion-beam geometry for the $4{}_{}{}^2{}_{}{}^{}S\to 4{}_{}{}^2{}_{}{}^{}P$ transition in ZnII at 75 eV. In addition, differential cross sections were calculated at energies between 15 and 100 eV in a five-state close-coupling approximation in which $4s$, $4p$, $3d^{9}4s^2$, $5s$, and $4d$ states were included. Agreement in shape between theory and experiment at 75 eV is excellent.