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

`DF-MP2`,*options*

invokes the density fitted MP2 program. The present implementation works
only without symmetry.
`RI-MP2` is an alias for the command `DF-MP2`.

The following options can be specified:

`BASIS_MP2`=*basis*:- Fitting basis set.
*basis*can either refer to a basis set defined in a`BASIS`block, or to a default fitting basis set (only available for correlation consistent basis sets). If a correlation consistent orbital basis set is used, the corresponding MP2 fitting basis is generated by default. In all other cases, the fitting basis must be defined. `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).

See section 15 for a more general description of density fitting. Expectation values and
gradients can also be computed with `DF-MP2`.

molpro@molpro.net 2019-06-17