Electron-impact excitation of silver

Abstract

We measure the differential cross sections (DCSs) for the electron-impact excitation of the combined (two fine-structure levels) resonant 4d105pP1/2,3/22 and 4d95s2D5/22 states in silver from the 4d105sS1/22 ground state. A comparison with the predictions of the relativistic distorted-wave (RDW) approximation model is carried out. Relativistic distorted-wave calculations are performed for each level separately and are combined to compare with the measurements. Both the experimental and theoretical results are obtained at incident electron energies E0 of 10, 20, 40, 60, 80, and 100 eV and scattering angles θ from 10° up to 150° (experiment) and from 0° to 180° (calculations). Absolute values for the experimental DCSs are obtained by normalizing relative DCSs to theoretical RDW results at 40° at all energies except at 10 eV, where we performed the normalization of the relative DCSs at 10° to our previous small-angle experimental DCS values [S. D. Tošić, Nucl. Instrum. Methods Phys. Res. Sect. B 279, 53 (2012)10.1016/j.nimb.2011.10.066]. The integrated cross sections, which include integral QI, momentum transfer QM, and viscosity QV cross sections, are determined by numerical integration of the absolute DCSs.