The data sets are collections of Maxwell-averaged radiative recombination coefficients (spontaneous free-bound transitions of Maxwellian electrons) represented by the reaction $X_{\rho}^{\left( z+1\right) +} + {\rm e}^- \rightarrow X_{i}^{z+} + h\nu .$

The coefficients exclude recombination via resonance states, that is dielectronic recombination. The latter is normally presented as a separate process in the independent isolated resonance approximation (see ADF09). The coefficients are resolved by initial metastable $\rho$ and final state $i$ and are tabulated as a function of electron temperature. The data sets are normally grouped in sub-directories for different iso-electronic sequences (of the initial ion). Most describe recombination to a set of LS terms from the ground up to some limiting n-shell typically one or two above the ground and span just light elements. ADF08 is a fundamental data format. Effective recombination coefficients, including dielectronic recombination, three-body recombination, cascading and re-ionisation losses occur as a derived data output from collisional–radiative modelling and such data are archived as a sub-class of data format ADF11.