COMPLEX MODEL OPTICAL-POTENTIAL FOR ELECTRON-SCATTERING FROM OXYGEN

We report calculations of the total (elastic plus inelastic) cross-sec tions for the e-O system over a wide energy range 10-5000 eV. A local complex optical potential is calculated for the system using the atomi c wavefunctions at the Hartree-Fock level. The real part of potential is composed of the attractive static, correlation polarisation and exc hange potential. The imaginary component of the complex potential is a function of target charge density, incident electron energy and mean excitation energy. The resulting complex potential is treated in varia ble phase approach to yield complex phase shifts and total cross-secti ons. The total and elastic cross-sections are compared with the other available results. The agreement is excellent for total cross-sections with other theoretical work at energies greater than 100 eV. We have excellent agreement for elastic cross-sections with the experimental a nd theoretical results at all the energies. The elastic differential c ross-sections are presented at 50 eV and 1000 eV. We fit the absorptio n cross-section values to Bethe asymptotic formula in high energy rang e (greater than or equal to 500 eV). Ionisation cross-sections above 1 000 eV are also deduced from the theory.