TOTAL (ELASTIC PLUS INELASTIC) CROSS-SECTIONS FOR ELECTRON-SCATTERING FROM DIATOMIC AND POLYATOMIC-MOLECULES AT 10-EV-5000-EV - H2, LI2, HF, CH4, N2, CO, C2H2, HCN, O2, HCL, H2S, PH3, SIH4, AND CO2

By employing a previously proposed model [A. Jain, Phys. Rev. A 34, 3703 (1986); J. Phys. B 22, 905 (1988)], we report calculations on the total (elastic plus inelastic) electron-scattering cross sections in a wide energy range (10-5000 eV) from several diatomic and polyatomic molecular targets (H-2 Li2, HF, CH4, N2, CO, C2H2, HCN, O2, HCl, H2S, PH3, SiH4, and CO2). A model complex optical potential (composed of static, exchange, polarization, and absorption terms) is calculated for each collision system from the corresponding molecular wave function at the Hartree-Fock level. The resulting complex optical potential, free from any adjustable parameter, is treated exactly in a variable-phase approach to yield scattering complex phase shifts and the total cross sections. In the intermediate- and high-energy region, the small contribution due to the nonspherical nature of the target is treated perturbatively in the first-order Born approximation. The present method is quite simple in nature and is able to reproduce fairly well the experimental total cross sections in the present energy region. Results are also given for individual elastic and absorption (accounting for all energetically possible inelastic processes in an approximate way) cross sections. In addition, we provide Born-Bethe parameters for all the above molecules including those of H2O and NH3. We have also examined the correlation between molecular properties and the total-cross-section parameter. For molecules possessing a permanent dipole or quadrupole moment, the present results are only roughly reliable above 100 eV.