Example: FDE geometry optimization: H2O-Li(+)¶

#!/bin/sh

# This example demonstrates how to perform a geometry optimization of an active
# subsystem (a lithium atom) in the presence of a frozen FDE fragment (the water
# molecule).

# Notes: 
# 
# a) Only the geometry of the active fragment will be relaxed (in this case, the
#    Li atom). The geometry of the FDE fragment (the water molecule) will not
#    change during the optimization.
#
# b) When performing geometry optimization ICW FDE one must:
#    - Disable symmetry ('Symmetry NoSym')
#    - It is advised to use the FullGrid option ('FDE => FullGrid')



# Prepare the water molecule fragment:
# ====================================

AMS_JOBNAME=Iso2 $AMSBIN/ams <<eor
System
  atoms
     O        0.0000000    0.0000000   -1.53403200
     H       -0.7782160    0.0000000   -2.13596600
     H        0.7782160    0.0000000   -2.13596600
  end
end

Task SinglePoint

Engine ADF
  basis
    core None
    type DZP
  end
  numericalquality Good
  symmetry NOSYM
  totalenergy
  xc
    lda
  end
  Relativity
    Level None
  End
EndEngine
eor

mv Iso2.results/adf.rkf t21.iso.rho2


# H2O-Li(+) Geometry optimization 
# (Li optimization in the presence of a 'frozen' water molecule)
# ==============================================================

AMS_JOBNAME=GO_FDE $AMSBIN/ams <<eor
System
  atoms
     LI        0.0000000    0.0000000    0.4529560
     O         0.0000000    0.0000000   -1.5340320  adf.f=rho2 region=frozen
     H        -0.7782160    0.0000000   -2.1359660  adf.f=rho2 region=frozen
     H         0.7782160    0.0000000   -2.1359660  adf.f=rho2 region=frozen
  end
  charge 1
end

Task GeometryOptimization

GeometryOptimization
   Convergence Step=1.0e-3
End

Properties
  Gradients Yes
End

Constraints
  Block frozen
End

Engine ADF
  fde
    fullgrid
    sdftenergy
    thomasfermi
  end
  fragments
     rho2 t21.iso.rho2 type=fde &
     SubEnd
  end
  basis
    core None
    type DZP
  end
  numericalquality Good
  symmetry NOSYM
  totalenergy
  xc
    lda
  end
  Relativity
    Level None
  End
EndEngine
eor

echo "Final Geometry"
echo ""
echo "Final Geometry after FDE optimization"

$AMSBIN/amsreport GO_FDE.results/adf.rkf 'distances#labels'