Precision

The three main issues that influence the accuracy of a calculation are: integration in real space, integration in k-space, and the quality of the basis set.

The key Accuracy controls (amongst others) the accuracy of the numerical integration scheme (barring a few technicalities the same scheme as used in the molecular ADF code). In the unlikely event that this single parameter does not suffice, you can fine-tune the integration scheme, see the description of the Integration. key-block of the ADF documentation. The other major key influencing the integration in reciprocal space is the KSpace parameter.