RATIONAL-FUNCTION FITS TO THE NONRESONANT ELASTIC DIFFERENTIAL CROSS-SECTIONS (DCS) FOR E + HE COLLISIONS, 0-DEGREES-180-DEGREES, 0.1 TO 1000 EV

Rational function fits are calculated for a representative set of elastic, nonresonant e + He differential cross sections (DCS) comprising: (1) the variational DCS of Nesbet (Phys. Rev. A 20, 58, 1979; 0.1-14 eV), (2) the eikonal DCS of Byron and Joachain (Phys. Rev. A 15, 128, 1977; 300-700 eV extrapolated to 1000 eV), and (3) the experimental data of Wagenaar et al. (J. Phys. B 19, 3124, 1986; 20-100 eV, 0°-10°), Register et al. (Phys. Rev. A 21, 1134, 1980; 20-200 eV), Bromberg (J. Chem. Phys. 61, 963, 1974; 200-700 eV) and Jansen et al. (J. Phys. B 9, 185, 1976; 200-1000 eV) with priorities in the order given. The fits, expressed as functions of the scattering angle with the impact energy as parameter, form smooth functions both over angles θ and energies E for easy interpolation. Maximum deviation from the data set is 10.4% for experiments and 20% for theory at low angles ≤10°, where theory deviates from experiments. Comparisons in symbolic form between the present fits and DCS results from the experimental and theoretical literature of the past 10 years are also given. © 1992.