\begin{table} \centering \begin{tabular}{l | c c c c c c c } & $E_0$ [eV] & $\sigma_0$ [cm$^2$] & $y_a$ & $P$ & $y_w$ & $y_0$ & $y_1$ \\ \hline\\[-0.5em] H$^0$ & 0.4298 & 5.475$\times 10^{-14}$ & 32.88 & 2.963 & 0 & 0 & 0 \\ He$^0$ & 13.61 & 9.492$\times 10^{-16}$ & 1.469 & 3.188 & 2.039 & 0.4434 & 2.136 \\ He$^+$ & 1.720 & 1.369$\times 10^{-14}$ & 32.88 & 2.963 & 0 & 0 & 0 \\ \end{tabular} \caption{Fitting parameters used for the ionizing cross section parametrizations given in eq.~\ref{eq:sigma-parametrizaiton}. The parametrization and these parameters are taken from \cite{vernerAtomicDataAstrophysics1996}. Note that the table given in the appendix of \cite{ramses-rt13} contains a typo in $E_0$ for He$^0$, and is off by a factor of 100.} \label{tab:cross-sections} \end{table}