#!/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 $AMSBIN/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 $AMSBIN/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"
$AMSBIN/dmpkf -n 1 Phonons.results/band.rkf --toc
echo "End TOC"