We suggest consistent sets of Ar+ + Ar and Ar++ + Ar differential and
integral cross sections for modeling ion scattering that take into acc
ount differential scattering data and the fact that symmetric charge t
ransfer collisions are one aspect of elastic scattering collisions. Th
ese suggestions make possible a considerable improvement in the accura
cy of future Monte Carlo calculations of the angular, energy, and temp
oral distributions of Ar+ and Ar++ ions passing through the electrode
sheaths of low-pressure, rf, and dc discharges in Ar. The cross sectio
ns necessary for a proper modeling of the energy dissipation in the ga
s and at the electrodes by fast neutral Ar atoms formed in symmetric-c
harge-transfer collisions of Ar+ and Ar++ with Ar are also reviewed.