Ratio of electron-impact ionization to OI 1356 Å dissociative excitation of O$_2$ and their cross sections

This dataset provides most recent measured cross sections of electron-impact ionization and OI 1356 Å dissociative excitation of O$_2$ and extrapolations as well as the ionization-to-excitation ratio for electrons with Maxwell energy distributions as collected or calculated in Duling et al. (2026) (Figure 1). Cross Sections The file cross_sections.txt contains measured or extrapolated cross sections for electron-impact ionization of O$_2$, OI 1356 Å dissociative excitation of O$_2$ and OI 1356 Å excitation of O as function of electron energy $W_e$ in the range 10$^1$-10$^5$ eV. Measured cross sections are linearly interpolated. For higher energies the measured cross sections are extrapolated using Bethe-Oppenheimer relations $AW_e^{-1} \ln\left(BW_e\right)$. The cross sections are total cross sections, meaning excitation interactions that excite to higher states than $^5S$ (1356 Å emission) but cascade to $^5S$ are included. The ionization cross sections include ionization interactions that produce (1) O$_2^+$, (2) O$^+$ + O$_2^{++}$ and (3) O$^{++}$. The measured cross sections are combined from the following publications: electron-impact ionization of O$_2$: $W_e\le$1000 eV Lindsay & Mangan (2003) (modified data from Straub et al. (1996))1000 eV $<W_e\le$20000 eV Schram et al. (1965)$W_e>$20000 eV extrapolation using the 600 eV $\le W_e\le$20000 eV data from Schram et al. (1965). OI 1356 Å dissociative excitation of O$_2$: $W_e\le$600 eV Kanik et al. (2003)$W_e>$600 eV extrapolation using the $W_e>$100 eV data from Kanik et al. (2003). OI 1356 Å excitation of O: 13 eV $<W_e\le$48 eV Julienne et al. (1976) The file contains the following columns: W_e_[eV] electron energy in eV ion_[cm^2] total cross section for electron-impact ionization of O$_2$ in cm$^2$ source source of electron-impact ionization cross section 1356_O2_[cm^2] total cross section for OI 1356 Å dissociative excitation of O$_2$ in cm$^2$ source source of OI 1356 Å dissociative excitation of O$_2$ cross section 1356_O_[cm^2] cross section for OI 1356 Å excitation of O in cm$^2$ source source of OI 1356 Å excitation of O cross section Ionization-to-excitation ratio The file ratio_rate_coefficients.txt contains interaction rate coefficients for electrons with Maxwell distributed energies as function of temperate $T$ in the range 1-10$^4$ eV, calculated as\begin{equation}k=\int_{0}^{10^5\mathrm{ eV}} f(v)\sigma(v)v \,\mathrm{d}v,\end{equation}where $\sigma(v)$ is the cross section of the interaction, $f(v)$ is the Maxwell speed distribution and $v=\sqrt{2W_e/m_e}$ is the speed of the electrons. The ratio\begin{equation}\beta_{\mathrm{ion/1356}}=\frac{k_{\mathrm{ion}}}{k_{\mathrm{1356}}}\end{equation}gives the ionization-to-excitation ratio and is used in Duling et al. (2026) to constrain electron-impact ionization rates from brightness observations of OI 1356 Å emissions. The file contains the following columns: T_[eV] temperature of the Maxwell distribution in eV k_ion_[cm^3/s] rate coefficient for electron-impact ionization of O$_2$ in cm$^3$/s k_1356_[cm^3/s] rate coefficient for OI 1356 Å dissociative excitation of O$_2$ in cm$^3$/s ratio_beta ionization-to-excitation ratio $\beta_{\mathrm{ion/1356}}$