24.2 Density-fitting MP2 (DF-MP2, RI-MP2)

Density-fitting MP2 (RI-MP2) can be performed with standard density or and Poisson fitting basis sets. The present implementation works only without symmetry. The input is as follows:

DF-MP2;

Optionally, a card DFIT can follow on which the following options can be specified:

BASIS_MP2=string:

Fitting basis sets, e.g., JKFIT (default) for standard density fitting or DENSITY:POISSON for mixed density/Poisson fitting. These basis sets must have been defined in a previous BASIS block.

THRAO=value:

Screening threshold for 3-index integrals in the AO basis

THRMO=value:

Screening threshold for 3-index integrals in the MO basis

THROV=value:

Screening threshold for 2-index integrals of fitting basis.

THRPROD=value:

Screening product threshold for first half transformation.

SPARSE=value:

If Non-zero, use sparse algorithm in second-half transformation (default).

RI-MP2 is an alias for the command DF-MP2. At present, expectation values and gradients cannot be computed with DF-MP2.