#!/bin/sh

# A phonon calculation should be performed at the equilibrium geometry.

# In the first calculation we optimize the geometry, including the lattice
# vectors. We also set the criteria a bit more strict.

echo "Geometry optimization"

AMS_JOBNAME=GO $ADFBIN/ams <<eor

System
  Atoms
    C   0.0 0.0 0.0
    C   1.23 0.7101408312 0.0
  END
  Lattice
    2.46 0.000000 0
    1.23 2.130422493 0
  End
End

Task GeometryOptimization

GeometryOptimization
  OptimizeLattice true
  Convergence Gradients=1e-5
  Method Quasi-Newton
End

Engine Band
  Title Graphene geometry optimization

  ! For Graphene we need to use a symmetric grid
  KSpace
    Symmetric KInteg=5
    Type Symmetric
  End

  StrainDerivatives
    Analytical false
  End

  Basis
    Type DZ
  end
EndEngine
eor

# In the second calculation we use the pre-optimized geometry. (See details of
# the Restart key block) Then we define a supercell and perform a phonon run by
# using Task and Phonons keys. Note that KSpace can be chosen
# a bit lower, since we now have a bigger unit cell.

echo "Phonon calculation"

AMS_JOBNAME=Phonons $ADFBIN/ams <<eor

LoadSystem
  File GO.results/ams.rkf
End

Task SinglePoint

Properties
  Phonons True
End

NumericalPhonons
  stepSize 0.0913
  SuperCell
    2 0
    0 2
  End
end

Engine Band
  Title Graphene phonon calc

  KSpace
    Symmetric KInteg=3
    Type Symmetric
  End

  Basis
    Type DZ
  end
EndEngine

eor

NSCM=1
export NSCM
echo ""
echo "Begin TOC"

$ADFBIN/dmpkf -n 1 Phonons.results/band.rkf --toc

echo "End TOC"