Estimates of maximal concentrations of singlet delta oxygen in a DC discharge

Plasma-chemical processes are considered, which define the concentrations of molecules of singlet delta oxygen (SDO) in plasma of a discharge in oxygen. Analytical expressions are derived and qualitative estimates are made of relative concentration of SDO in a dc discharge, which take into account the loss of SDO molecules during interaction with plasma electrons and deactivation on the walls. It is demonstrated that the optimal concentration of plasma is required for obtaining the maximal concentration of SDO. The maximal relative concentration of SDO at optimal values of $E/N$ in the range of $9$–$13$ Td may be $\sim20\%$.