Excitation of the Resonance Lines of Ar by Electrons

'Polarization-free' measurements are presented of the electron impact excitation of the 1048 Å and 1067 Å resonance lines of argon in the energy range 10–2000 eV. Cross sections are made absolute by normalizing to the optical oscillator strength of the 1048 Å line. Cascade is shown to play a major role in the excitation of the 4s levels. Comparison is made with other experimental results and with theory where available.