CamCASP-commands

! The grid matters here. These parameters should be sufficient.
 
BEGIN GRID
  Molecule  A
  Angular 200
  Radial  100
END
 
BEGIN GRID
  Molecule  B
  Angular 200
  Radial  100
END
 
! Set this to FALSE as the auxiliary basis sets are type-MC
 
SET DF
  REDO-DF-ON-ROTATION   False
END
 
! Perform the OO-type density fitting for each of the monomers
 
BEGIN DF
  Molecule  A
  Type OO
  Eta = 0.0 
  Lambda = 0.0 
  Gamma = 0.0
  Print only normalization constraints
  Solver LU
END
BEGIN DF
  Molecule  B
  Type OO
  Eta = 0.0 
  Lambda = 0.0 
  Gamma = 0.0
  Print only normalization constraints
  Solver LU
END
 
! Setting for the ISA calculation. But we do not perform the ISA here:
! We read a pre-computed solution from file using the RESTART block.
 
Begin Stockholder
  Molecule  A
  DF = Drho
  W-INIT = ONE-GTO   ALPHA0 = 1.0
  ISA-Algorithm A   Zeta = 1.0
  DF-PARAMETERS Lambda = 1000.0
  Solver LU
  Convergence
    Convergence-Type W
    EPS-Norm = 1.0e-10
    EPS-Q    = 1.0e-4
    Max-Iter = 60
    W-Damping = 0.0
    W-Mix-Fraction = 0.0  Skip-Iterations = 20
    W-Eps = 0.17  S-Block-Only Couple  Switch-On-Eps-Norm = 1.0e-04
    Positive-W   Lambda = 0.0001 for Max-Alpha = 2.0  AUTO
    Tail-Iterations = 30
  End
  W-TAILS
    Func = 1
    R1-Multiplier = 1.5
    R2-Multiplier = 2.5
    Fit-Type = 3
    W-Tests
  END
  Restart
    File    DEFAULT
    Iterate No
    Test    Yes
  End
End
 
! Useful to calculate multipole to make sure it was all OK
! Note that without iterations these may not come out accurate.
 
Begin Multipoles
  Molecule  A
  DF Type ISA
  Rank      4
End
Begin Multipoles
  Molecule  A
  DF Type ISA-GRID
  Rank      4
End
 
! Same for the second molecule
 
Begin Stockholder
  Molecule  B
  DF = Drho
  W-INIT = ONE-GTO   ALPHA0 = 1.0
  ISA-Algorithm A  Zeta = 1.0
  DF-PARAMETERS Lambda = 1000.0
  Solver LU
  Convergence
    Convergence-Type W
    EPS-Norm = 1.0e-10
    EPS-Q    = 1.0e-4
    Max-Iter = 60
    W-Damping = 0.0
    W-Mix-Fraction = 0.0  Skip-Iterations = 20
    W-Eps = 0.17  S-Block-Only Couple  Switch-On-Eps-Norm = 1.0e-04
    Positive-W   Lambda = 0.0001 for Max-Alpha = 2.0  AUTO
    Tail-Iterations = 30
  End
  W-TAILS
    Func = 1
    R1-Multiplier = 1.5
    R2-Multiplier = 2.5
    Fit-Type = 3
    W-Tests
  END
  Restart
    File   DEFAULT
    Iterate No
    Test    Yes
  End
End
 
Begin Multipoles
  Molecule  B
  DF Type ISA
  Rank      4
End
Begin Multipoles
  Molecule  B
  DF Type ISA-GRID
  Rank      4
End
 
! Integral switches in the energy modules
 
Set E1elst
  Integral switch = 0
End
Set E1exch
  ! Overlap integrals Algorithm DF without constraints
  Integral switch = 0
End
 
! This is where the distributed density-overlap parameters are set.
! We use the ISA-based partitioning on a density obtained using DF without
! constraints. The ISA-based partitioning algorithm can be done
! in basis-space (not a good idea) or in real-space. The latter is
! much more accurate, but takes much longer.
! We set the grid parameters for the integration. These parameters
! are known to work well.
 
Set Dist-Dens-Overlap
  Type ISA
  DF-Type OO without constraints
  ISA-DIST-TYPE GRID-ALG1
  DF-INTEGRAL-SWITCH = 0
  Integration-Grid  Radial 40  Angular 200
  ISA-Options TAIL-FIX = False
  Print-Results No
End
 
! Energy-scan for E(1)elst and overlap only. The former cost nothing
! more and server as a check on the results.
!
! If you also include E1exch then you can make a plot of 
! E1exch vs the total overlap 'energy' in the file energy_file.dat
! and see if there is a correlation. There should be!
!
! E1elst will not be believable as we have used monomer basis sets
! in this calculation, and we need at least a DC auxiliary basis to 
! get this energy correctly.
 
Begin Energy-Scan
  Energy  E1elst & Overlap ( E1exch )
  Units Bohr
  ! The dimer geometries should be in a file called dimers.geom:
  #include dimers.geom
End
 
End-CamCASP-commands