:term:`DF_BASIS_MP2 <DF_BASIS_MP2 (DFMP2)>` """"""""""""""""""""""""""""""""""""""""""" Auxiliary basis set for MP2 density fitting computations. :ref:`Defaults <apdx:basisFamily>` to a RI basis. * **Type**: string * **Possible Values**: :ref:`basis string <apdx:basisElement>` * **Default**: No Default