## Electron impact ionisation coefficients

The data sets are collections of Maxwell averaged electron impact ionisation rate coefficients represented by the reactions $X^{z+}_i + {\rm e}^- \rightarrow X^{\left( z+1\right) +}_\rho +{\rm e}^- +{\rm e}^- , \\ X^{z+}_i + {\rm e}^- \rightarrow X^{*\left( z\right) +} +{\rm e}^- \rightarrow X^{\left( z+1\right) +}_\rho +{\rm e}^- +{\rm e}^- .$

That is the coefficients combine both direct ionisation and excitation/autoionisation. The tabulations are resolved by initial state $i$ and final metastable $\rho$, with the initial state also mostly spanning just metastables. The rate coefficients are tabulated as a function of electron temperature. The data sets are typically grouped in sub-directories for a particular element. ADF07 is a fundamental data format. It should be noted that it does not include step-wise ionisation via multiple sequential excitations and then a final ionising collision. Effective ionisation coefficients, including step-wise ionisation, occur as a derived data output from collisional–radiative modelling and such data are archived as a sub-class of data format ADF11.