(color online) Differential cross sections for elastic scattering of electrons by Ar at incident energies of (a) 3 eV, (b) 5 eV, (c) 10 eV, (d) 20 eV, (e) 50 eV, and (f) 100 eV. The experimental data are taken from Srivastava et al.,^[27] Nahar and Wadehra,^[16] Williams and Willis,^[28] DuBois and Rudd,^[29] and Vušković and Kurepa.^[30]