From Diracwiki

This page describes unreleased functionality. The keywords may not be available in your version of DIRAC.

Fitting basis set

In the development version of DIRAC it is now possible to make use of density fitting. In such calculations, it is mandatory to include a basis set used to expand the density.

This is done adding a line with the FTSET keyword to the MOLECULE file, after the coordinates for a given atom type

FTSET [options]

Basically all the options available in the definition of large or small basis sets are applicable to the fit set (i.e. the use of a set from the library, explicitly typed basis, even/well-tempered etc). Here are some examples:

Basis sets from the basis set library

DIRAC
Water
aug-cc-pVDZ basis (note that a tight p has NOT been added)
C   2    2  X  Y
        8.    1
O      .0000000000        0.0000000000        -.2249058930
LARGE BASIS cc-pVDZ
FTSET BASIS Ahlrichs-Coulomb-Fit