#! /bin/sh

# This example shall illustrate the use of the Fragment keywords in combination
# with the PEDA keyword to perform the PEDA. For this example two fragment
# calculations are necessary to calculate the unperturbed eigensystems of the
# MgO slab and CO fragment.

# == Fragment calculations ==

# ------------------------------ MgO slab ------------------------

AMS_JOBNAME=MgO $AMSBIN/ams <<eor

Task SinglePoint 

System
  Atoms
     Mg  0.00000000       0.00000000       0.00000000
     Mg  1.50260191      -1.50260191      -2.12400000
     Mg  0.00000000       0.00000000      -4.24800000
     Mg  3.00520382       0.00000000       0.00000000
     Mg  1.50260191       1.50260191      -2.12400000
     Mg  3.00520382       0.00000000      -4.24800000
     O   1.50260191      -1.50260191       0.00200000
     O   0.00000000       0.00000000      -2.12400000
     O   1.50260191      -1.50260191      -4.25000000
     O   1.50260191       1.50260191       0.00200000
     O   3.00520382       0.00000000      -2.12400000
     O   1.50260191       1.50260191      -4.25000000
  End

  Lattice
         3.00520382      -3.00520382       0.00000000
         3.00520382       3.00520382       0.00000000
  End
End

Engine Band 
  Title MgO surface

  skip dos

  KSpace
    Regular
      NumberOfPoints 3 3
    End
  End

  XC
     GGA PBE
  End

  Basis
     Type TZP
     Core small
  End
EndEngine 

eor

#------------------------------ CO fragment ------------------------

AMS_JOBNAME=CO $AMSBIN/ams <<eor

Task SinglePoint 

System
  Atoms 
     C   0.00000000       0.00000000       2.61000000
     O   0.00000000       0.00000000       3.737000000
  End

  Lattice
         3.00520382      -3.00520382       0.00000000
         3.00520382       3.00520382       0.00000000
  End
End

Engine Band 
  Title CO fragment

  KSpace
    Regular
      NumberOfPoints 3 3
    End
  End

  XC
     GGA PBE
  End
   
  Basis
     Type TZP
     Core small
  End
EndEngine
eor

# == PEDA calculation ==

# The two result files, MgO.kf and CO.kf, can now be used to perform the
# PEDA. Here, the mapping of the atoms of the PEDA calculation and the fragment
# calculations is necessary. And the used grid points in reciprocal space have
# to be identical in all three calculations.

# ----------------------------- PEDA calculation ------------------------

$AMSBIN/ams <<eor

Task SinglePoint 

System 
  Atoms
     Mg.frag_MgO  0.00000000       0.00000000       0.00000000
     Mg.frag_MgO  1.50260191      -1.50260191      -2.12400000
     Mg.frag_MgO  0.00000000       0.00000000      -4.24800000
     Mg.frag_MgO  3.00520382       0.00000000       0.00000000
     Mg.frag_MgO  1.50260191       1.50260191      -2.12400000
     Mg.frag_MgO  3.00520382       0.00000000      -4.24800000
     O.frag_MgO   1.50260191      -1.50260191       0.00200000
     O.frag_MgO   0.00000000       0.00000000      -2.12400000
     O.frag_MgO   1.50260191      -1.50260191      -4.25000000
     O.frag_MgO   1.50260191       1.50260191       0.00200000
     O.frag_MgO   3.00520382       0.00000000      -2.12400000
     O.frag_MgO   1.50260191       1.50260191      -4.25000000
     O.frag_CO    0.00000000       0.00000000       3.73700000
     C.frag_CO    0.00000000       0.00000000       2.61000000
  End

  Lattice
         3.00520382      -3.00520382       0.00000000
         3.00520382       3.00520382       0.00000000
  End
End

Engine Band   
  Title PEDA

  KSpace
    Regular
      NumberOfPoints 3 3
    End
  End

  XC
     GGA PBE
  End
   
  fragment 
    filename MgO.results/band.rkf
    AtomMapping
       1  1
       2  2
       3  3
       4  4
       5  5
       6  6
       7  7
       8  8
       9  9
       10 10
       11 11
       12 12
     End
  end

  fragment 
    filename CO.results/band.rkf
    AtomMapping
       2  13
       1  14
     End
  end

  PEDA

  Basis
     Type TZP
     Core small
  End
EndEngine

eor

# In the output file the results can be found in the PEDA block after the Energy
# Analysis.