Table 1 Collision frequencies for momentum transfer between ions and electrons with neutrals (s⁻¹)

Molecular oxygen (\({\rm O}_{2}^{+}\))–neutral

\(\nu_{\rm in} = \mathop \sum \nolimits_{k = 1}^{9} \nu_{k}\)

  \(\nu_{{{\rm O}_{2}^{+} \rightarrow {\rm O}}} = 2.31 \times 10^{- 10}\,n\left({\rm O} \right)\)

 \(\nu_{{{\rm O}_{2}^{+} \rightarrow {\rm O}_{2}}} = 2.59 \times 10^{- 11} n\left({{\rm O}_{2}} \right)T^{{\frac{1}{2}}}\,(1 - 0.073 \log T)^{2}\)

 \(\nu_{{{\rm O}_{2}^{+} \rightarrow {\rm N}_{2}}} = 4.13 \times 10^{- 10}\,n\left({{\rm N}_{2}} \right)\)

Nitric oxide (\({\rm NO}^{+}\))–neutral

  \(\nu_{{{\rm NO}^{+} \rightarrow {\rm O}}} = 2.44 \times 10^{- 10}\,n\left({\rm O} \right)\)

 \(\nu_{{{\rm NO}^{+} \rightarrow {\rm O}_{2}}} = 4.27 \times 10^{- 10}\,n\left({{\rm O}_{2}} \right)\)

 \(\nu_{{{\rm NO}^{+} \rightarrow {\rm N}_{2}}} = 4.34 \times 10^{- 10}\,n\left({{\rm N}_{2}} \right)\)

Atomic oxygen (\({\rm O}^{+}\))–neutral

 \(\nu_{{{\rm O}^{+} \rightarrow {\rm O}}} = 4.45 \times 10^{- 11} n\left({\rm O }\right)T^{{\frac{1}{2}}}\,(1.04 - 0.067 \log T)^{2}\)

 \(\nu_{{{\rm O}^{+} \rightarrow {\rm O}_{2}}} = 6.64 \times 10^{- 10}\,n\left({{\rm O}_{2}} \right)\)

 \(\nu_{{{\rm O}^{+} \rightarrow {\rm N}_{2}}} = 6.82 \times 10^{- 10}\,n\left({{\rm N}_{2}} \right)\)

Electron–neutral

\(\nu_{\rm en} = \mathop \sum \nolimits_{k = 1}^{3} \nu_{k}\)

 \(\nu_{{{\rm e} \rightarrow {\rm O}}} = 8.9 \times 10^{- 11} n\left({\rm O} \right)\left({1 + 5.7 \times 10^{- 4} T} \right)\,T^{{\frac{1}{2}}}\)

 \(\nu_{{{\rm e}\rightarrow {\rm O}_{2}}} = 1.82 \times 10^{- 10} n\left({{\rm O}_{2}} \right)\left({1 + 3.6 \times 10^{- 2} T^{{\frac{1}{2}}}} \right)\,T^{{\frac{1}{2}}}\)

 \(\nu_{{{\rm e}\rightarrow {\rm N}_{2}}} = 2.33 \times 10^{- 11} n\left({{\rm N}_{2}} \right)\left({1 - 1.21 \times 10^{- 4} T} \right)T\)