Calculations of electron loss cross sections for oxygen ions in gaseous media

In the ion energy range 0.1-200 MeV/nucleon, the cross sections $\sigma_{i, i+1}$ of electron loss by oxygen ions with charges $i=1 \div 7$ in hydrogen, nitrogen, and argon are calculated. The values of the cross sections of electron loss by multielectron ions are obtained by summing up partial cross sections $\sigma_{nl}$ of electron losses from all $nl$ ion shells. The charge composition in the oxygen ion beams after passing the specified substance layer is determined. Most calculation results are fairly consistent with the experimental data available.