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37.8 Options

SAPT_LEVEL
Set to 1 for first-order terms ( $E_\mathrm{pol}^{(1)}$ and $E_\mathrm{exch}^{(1)}$), to 2 for additional second order (exchange-)induction terms ( $E_\mathrm{ind}^{(2)}$ and $E_\mathrm{exch-ind}^{(2)}$) and 3 for all first- and second-order terms (including then also $E_\mathrm{disp}^{(2)}$ and $E_\mathrm{exch-disp}^{(2)}$) (default 3)
SAPT_FITLEVEL
Level of density fitting approximations in SAPT which can have values 0 to 3 (default 0)
SAPT_ICPKS
Switch between iterative (=1) and non-iterative (=0) solution of coupled-perturbed Kohn-Sham equations (default 0)
SAPT_CPKSTHR
Threshold for density matrix convergency in the coupled-perturbed Kohn-Sham program (default 1.d-6).
SAPT_CPKMAXIT
Maximum number of iterations in the coupled-perturbed Kohn-Sham program (default 50).
SAPT_FROZENA
Number of frozen electrons in the response calculations for monomer A (default 0)

The following parameters are of importance if SAPT_FITLEVEL$>$0:

SAPT_NFRQ_DISP
Number of frequencies for the Casimir-Polder integration (default 12)
SAPT_NORM_DISP
Norm for the density fitting which can be either COULOMB or NATURAL (default COULOMB)
SAPT_DISP_N4
Can speedup the calculation of the dispersion energy by $N^4$ scaling (default 1)
THR_XCKERN
Density threshold for the xc kernel matrix elements (default 1.d-8)
FIT_XCKERN
Fit both sides of the xc kernel (default 0)
SAPT_DISK
If 0 write all dimer amplitudes to file, if 1 write 3-index response propagators to file and if 2 write 3-index response propagators compressed to file. The latter two variants save disk space but need more CPU time to compute $E^{(2)}_\mathrm{exch-disp}$ (default 0)
COMPRESS_THR
If SAPT_DISK=2 this value determines the compression cutoff (default 1d-12)
UNCOUPLED
If SAPT_DISK$>$0 calculate also uncoupled (exchange-)dispersion energies (default false)
THRAO
Threshold for AO 3-index integrals (default 1.d-12)
THRMO
Threshold for MO 3-index integrals (default 1.d-8)
THROV
Threshold for AO 2-index integrals (default 1.d-10)
THRPROD
Product threshold for first half transformation (default 1.d-8)
THRSW
Threshold for Schwarz screening (default 1.d-5)
C6
Calculate dispersion coefficients for the two monomers (Note that the full dimer basis set is used in each case and that a closer distance of the monomers can perturb the result).
XCKERN_NBLOCK
number of grid points treated together as a block for (aux$\vert$f$_\mathrm{xc}\vert$occ$\times$virt) integrals (default 128)
CFAC
factor for VWN correlation in ALDA xc-kernel (default 1.d0)

The last threshold values for the 2- and 3-index integrals should not be set higher in density fitting calculations as this can cause lower accuracies in the interaction terms. In addition SAPT knows the following subcommands:

MONOMERA
Stores informations (like number of electrons, etc.) about previous monomer A calculation
MONOMERB
See above
INTERMOL
Starts the SAPT calculation

INTERMOL may have the following subkeywords:

CA
Record number of wave function for monomer A (always needed)
CB
Record number of wave function for monomer B (always needed)
SAPTLEVEL
See above
FITLEVEL
See above
ICPKS
See above
FROZA
See above
FROZB
See above
NLEXFAC
Amount of nonlocal exact exchange in hybrid DFT-SAPT calculations
CPKSTHR
Threshold for density matrix convergency in the coupled-perturbed Kohn-Sham program.
CPKSMAXIT
Maximum number of iterations in the coupled-perturbed Kohn-Sham program.



Next: 37.9 DFSAPT: a density-fitting Up: 37 SYMMETRY-ADAPTED INTERMOLECULAR PERTURBATION Previous: 37.7.3 DF-DFT-SAPT calculation of   Contents   Index   PDF

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