  This work presents a reaction mechanism for oxygen plasmas, i.e. a set of
reactions and corresponding rate coefficients that are validated against
benchmark experiments. The kinetic scheme is validated in a DC glow discharge
for gas pressures of 0.2-10 Torr and currents of 10-40 mA, using the 0D LisbOn
KInetics (LoKI) simulation tool and available experimental data. The comparison
comprises not only the densities of the main species in the discharge -
$\mathrm{O_2(X^3\Sigma_g^-)}$, $\mathrm{O_2(a^1\Delta_g)}$,
$\mathrm{O_2(b^1\Sigma_g^+)}$ and $\mathrm{O(^3P)}$ - but also the
self-consistent calculation of the reduced electric field and the gas
temperature. The main processes involved in the creation and destruction of
these species are identified. Moreover, the results show that the oxygen atoms
play a dominant role in gas heating, via recombination at the wall and
quenching of $\mathrm{O_2(X^3\Sigma_g^-,v)}$ vibrations and $\mathrm{O_2}$
electronically-excited states. It is argued that the development and validation
of kinetic schemes for plasma chemistry should adopt a paradigm based on the
comparison against standard validation tests, as it is done in electron swarm
validation of cross sections.
