Example: PIM: optimization N2 on silver cluster Ag68¶

$ADFBIN/adf << eor
TITLE DIM/QM Gradient Test, N2 on Ag68

ATOMS
N       0.0000000000    0.0000000000    2.5000000000
N       0.0000000000    0.0000000000    3.5000000000
END

BASIS
 type TZP
 core none
END

SYMMETRY NOSYM

CHARGE 0

SCF
 Iterations 100
 Converge 1e-6
END

BeckeGrid
 Quality good
End

XC
 GGA Becke Perdew
END

:: It is suggested to use a full scf for the first
:: geometry iteration of a DIM/QM optimization
FULLSCF
GEOMETRY
 :: DIM/QM geometry optimization must be done in Cartesian coordinates
 Optim Cartesian
 :: For a DIM/QM geometry optimization
 :: it is suggested to use tighter convergence criterion
 Converge Grad=1E-4
 :: We are only interested in testing the gradients, so look at first iteration only
 Iterations 1
END

SAVE  TAPE21

DIMQM
:: Choose DIM/QM Methods:
:: Here PIM with screening
 PIM
 ALGORITHM DIRECT
 SCREEN EXP 1.0
:: Choose DIM/QM FORCE FIELD Method
:: First, we choose the Lennard-Jones 12-6 pot.
 FORCEFIELD LJ12-6
:: Next, we make the FORCE FIELD coordination dependent
 COORDDEPEND
:: Finally, we will add Chemisorption corrects
 CHEMISORPTION
:: User many add additional FORCE FIELD parameters
:: Adding coordination dependent parameters (in a.u.)
::        ATOM   E_0       E_1       R_0       R_1        CN_max    R_max     R_min
 COORDPAR  Ag   0.003000  0.000800  3.250000  3.650000  12.000000  9.448600  5.669200
:: Adding Chemisorption parameters
::        ATOM    E_0       E_1       R_0       R_1       CUTOFF
 CHEMPAR   N     0.275000  0.052500  0.800000  0.900000  4.913000
:: To print the DIM/QM gradients
DEBUG
END

DIMPAR
Ag
 rad=1.4445
SUBEND
XYZ
68
Ag     -1.2626801699   -1.1212553334   -7.5641602542
Ag      1.8701101821   -2.1177433283   -0.4836551986
...
SUBEND
END
eor