MOLPRO

23 MØLLER PLESSET PERTURBATION THEORY 180
THRMAX
initial CPHF convergence threshold in geometry optimizations. Once
the geometry is converged to a certain accuarcy (depending on OPTCONV),
the threshold is stepwise reduced to THRMIN.
The default is THRMAX=min(1.d-6,THRMIN*100); Values larger than
1.d-6 are ignored.
MAXIT Maxmimum number of iterations (default 50).
SHIFT Level shift for CPHF (default 0.1).
DIIS First macroiteration in which DIIS is used (default 1)
DISM
SAVE
START
First microiteration in which DIIS is used (default 1; in microiterations
the core contribution is frozen).
Record on which the CPHF solution can be saved for later restarts.
The solution is saved automatically in geometry optimizations and
frequency calculations.
Record from which initial guess is read. A starting guess is read automatically
in geometry optimizations and frequency calculations.
23.4 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:
THRMO=value:
THROV=value:
THRPROD=value:
SPARSE=value:
Screening threshold for 3-index integrals in the AO basis
Screening threshold for 3-index integrals in the MO basis
Screening threshold for 2-index integrals of fitting basis.
Screening product threshold for first half transformation.
If Non-zero, use sparse algorithm in second-half transformation (default).
See section 15 for a more general description of density fitting.
At present, expectation values and gradients cannot be computed with DF-MP2, but work with
the local variant DF-LMP2.
23.5 Spin-component scaled MP2 (SCS-MP2)
The spin-component scaled MP2 energy as proposed by Grimme (J. Chem. Phys. 118, 9095
(2003)) is printed automatically using the default scaling factors (1.2 for antiparallel spin, 1/3
for parallel spin). These factors can be modified using the options SCSFACS and SCSFACT,
respectively, i.e.