An electron beam, characterized by a high-angular discrimination (≃0.7°), has been used to measure the total (elastic plus inelastic) cross section of H2O in the energy range 3-100 eV. Broad coincidence is found with recent experiments, including a pronounced shoulder in the 6-12 eV region. However, at energies 6 eV, the present cross sections are ≃30% higher. Furthermore, forward scattering has been probed in the angular range 0°-3.5° and measures of the average (rotationally and vibrationally summed) differential elastic cross sections for incident energies ≤12 eV are obtained at a scattering angle ≃1. The measurements, which provide the first test of theoretical predictions in an angular region experimentally unexplored until now, are found to be within 1 standard deviation of corresponding ab initio R-matrix calculations.
ASJC Scopus subject areas
- Physics and Astronomy(all)