Electron scattering by ytterbium: I. Excitation of the 4f146s6p 1P1 resonance state and elastic collision

Abstract

Differential cross sections (DCSs) for electron-impact excitation of the 4f146s6p 1P1 resonance state of ytterbium were measured at 10, 20, 40, 60 and 80 eV incident electron energies (E0) and scattering angles (θ) between 2° and 150°. The absolute DCS scale for the 1P1 state was determined through normalization of its relative DCSs to the optical oscillator strength using the forward scattering function method. DCSs for elastic electron scattering by ytterbium were measured at the same energies for θ between 10° and 150°. Elastic-to-inelastic intensity ratios were obtained from energy-loss spectra recorded with overall energy resolution of 65 meV (FWHM) and angular resolution of 1.5°. Both inelastic and elastic DCSs were extrapolated to 0° and 180° and numerically integrated to yield integral, momentum transfer and viscosity cross sections. Our results are compared with scarce experimental and theoretical data.