Search

We present experimental and theoretical differential cross sections for elastic electron scattering from xenon. Two independent measurements were carried out at (1) Chungnam National University for incident electron energies of 10, 20, 30, 50 and 100 eV and scattering angles from 10° up to 180° and (2) the Institute of Physics in Belgrade for incident electron energies of 20, 30 and 50 eV and scattering angles from 10° up to 150°. While these latter measurements do not cover the full angular range up to 180°, they still extend somewhat higher in scattering angle than previous measurements. It would appear that the theoretical treatment of intermediate energy elastic scattering from xenon is sensitive to the inclusion of absorption effects, particularly at backward scattering angles. This observation plus the previous results for the case of krypton indicates that the role of absorption is generally quite important for the rare gases.

Differential cross sections (DCS) for electron-impact excitation of the 3s3p 1P1state in magnesium at incident electron energies E0= 10, 15, 20, 40, 60, 80 and 100 eV have been measured and corresponding calculations carried out. Scattered-electron intensities were measured over a wide range of scattering angles (10°-150°) and normalized to the DCSs at 10° experimentally obtained by Filipovic et al(2006 Int. J. Mass Spectrom. 25166). Corresponding calculations have been conducted in the relativistic distorted-wave approximation. Integrated (integral, momentum transfer and viscosity) cross sections are determined by numerical integration of our DCSs. The results are analysed and compared with previous experimental data and theoretical calculations.

Differential cross sections (DCSs) for electron-impact excitation of the 4f146s6p3P1(2.231 eV) state of ytterbium have been determined experimentally at incident electron energies, E0= 10, 20 and 40 eV, and scattering angles (?) from 2° to 150° (at 10 eV from 10°). Also, DCSs for the 4f145d6s 1D2(3.432 eV) and 4f135d6s2(7/2, 5/2)1(3.578 eV) states at E0= 10 and 20 eV, and the 4f146s7p 1P1(5.029 eV) state at 20 and 40 eV have been measured. These measurements were performed at ? between 10° and 150° for the 4f145d6s 1D2and 4f135d6s2(7/2, 5/2)1states, and between 2° and 150° for the 4f146s7p 1P1state. The inelastic-to-reference inelastic (the 4f146s6p 1P1resonance state) intensity ratios were obtained from energy-loss spectra recorded with overall energy resolution of 65 meV (FWHM) and angular resolution of 1.5°. Using these ratios and DCSs for the reference state (Predojevic et al2005 J. Phys. B: At. Mol. Opt. Phys.381329) the absolute inelastic DCSs were determined. In this way the obtained DCSs were extrapolated to 0° and 180° and numerically integrated to yield integral, momentum transfer and viscosity cross sections. Our results are compared with available calculated values and experimental data.

The experimental and theoretical studies of elastic electron scattering by calcium atom have been made. The experimental investigation was carried out using a crossed electron-atom beam technique. The measurements were performed at electron-impact energies (E0) of 10, 20, 40, 60 and 100 eV and for a range of scattering angles (?) from 10° up to 150°. The absolute differential cross sections (DCSs) have been obtained from the elastic-to-inelastic (the resonant 41P0state) intensity ratio at ? = 10° at each E0. Calculations have been performed in the optical potential approximation for the same E0and ? between 0° and 180°. Results for DCSs and integrated (integral, momentum transfer and viscosity) cross sections are presented and compared with those predicted by existing calculations.

Elastic scattering of electrons by krypton atom was investigated both experimentally and theoretically. Differential cross sections (DCSs) were measured at fixed incident energies from 20 eV to 80 eV as a function of scattering angle (10°-150°). From 100 eV, DCSs were measured as a function of both incident electron energy (100-260 eV) and scattering angle (30°-110°), in small steps around minima. The energy dependence of the angular positions of DCS minima was determined. Theoretical results were obtained in terms of a model of phenomenological complex potential with allowance for spin-orbit interaction. Two data sets were calculated, with and without an absorption potential, and compared to experimental results. The improvements and deteriorations in agreement with measurements upon inclusion of absorption effects are discussed.

Differential cross sections (DCSs) for electron-impact excitation of the 4f146s6p 1P1resonance state of ytterbium were measured at 10, 20, 40, 60 and 80 eV incident electron energies (E0) and scattering angles (?) between 2° and 150°. The absolute DCS scale for the 1P1state 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 ? 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.