MOLPRO

31 EXPLICITLY CORRELATED METHODS 234
We recommend to specify options only when necessary and when it is well understood what
they mean!
Options for canonical and local versions:
DF BASIS=basis
Select the basis for density fitting (see section 15 for details). basis
can either refer to a set name defined in the basis block, or to a default
MP2 fitting basis (e.g., DF BASIS=VTZ generates the VTZ/MP2FIT
basis). By default, the MP2FIT basis that corresponds to the orbital
basis is used.
DF BASIS EXCH=basis Select the density fitting basis for computing the exchange and
Fock operators. By default, the JKFIT basis sets which correspond
to the orbital basis are used.
RI BASIS=basis
CONTEXT=context
ANSATZ=ansatz
GEM BASIS
GEM TYPE
Select the basis for the resolution of the identity (RI). This can refer
to a default basis set or a set name defined in a basis block. For F12
methods the Hartree-Fock JKFIT basis sets perform well for the RI,
despite having been optimized for other purposes. These sets are used
by default for the AVnZ orbital basis sets. The basis type can be appended
to the basis name after a slash, e.g.
RI BASIS=AVQZ/JKFIT would use the specified JKFIT set, or
RI BASIS=AVQZ/OPTRI would use the optimized CABS basis sets
of Peterson et al. These are recommended for the AVnZ and VnZ-F12
basis sets and used by default for the latter ones. Note that each OP-
TRI basis is associated to a specific orbital basis. Therefore, the name
of the OPTRI basis must either be the same as that of the orbital basis,
or be omitted, e.g., RI BASIS=OPTRI selects automatically the
correct set for the current orbital basis.
In case of R12-methods (which are not recommended to be used),
the RI basis should be chosen to be a large uncontracted AO basis
(at least AVQZ). Contraction/uncontraction can be forced appending
(CONTRACT) or (UNCONTRACT) to the basis name, e.g.,
RI BASIS=AVQZ(UNCONTRACT)/ORBITAL. If other options are
given in parenthesis, these can be separated by commas, e.g.,
RI BASIS=AVQZ(f/d,UNCONTRACT)/ORBITAL.
Alternative forms, which should work as well, are
RI BASIS=AVQZ(f/d)(UNCONTRACT)/ORBITAL
or
RI BASIS=AVQZ(f/d)/ORBITAL(UNCONTRACT).
Note that the CONTRACT/UNCONTRACT option cannot be used
with basis set names previously defined in a basis block.
Can be used to change the default type for the RI basis, e.g. CONTEXT=OPTRI
will use the OPTRI basis sets that correspond to the VnZ-F12 or
AVnZ basis sets.
Select the explicitly correlated ansatz ansatz methods. See section
31.7 for the possibilities and further details.
Basis set name for geminal expansion; atom labels are ignored. This
can either be OPTFULL (full nonlinear fit of the geminal expansion),
EVEN (even tempered fit), or refer to a set name defined in a previous
BASIS block. Default is OPTFULL.
Frozen geminal type: LINEAR or SLATER, default is SLATER.