#! /bin/sh

# GW calculation for Water. By default. The highest 5 occupied and lowest 5
# unoccupied states are calculated.

# We use an all-electron basis set since core-correlation effects are important. 
# A large basis set is recommended for relatively well converged QP energies. 
# With the 5Z GTO type basis set, we expect the QP energies to be converged
# within 0.1 eV.

# Fot this example we will use the GGA PBE.
# This is NOT a recommended starting point for a G0W0 calculation. 
# However, the eigenvalue-only self-consistency removes most of the 
# starting point dependence of the functional. 
# Thererfore, PBE is a reasonable choice.  

# RECOMMENDED: VeryGood numerical quality, 
# especially in self-consistent GW calculations. 

# We calculate the auxiliary fit set from products of primary basis functions.
# When the primary basis contains functions with angular momenta of l=5, like
# the cc-pV5Z one, we need functions in the fit with angular momenta of l=10.
# Building the auxiliary basis from fit funtions ensures this. 

$AMSBIN/ams << eor
Symmetry
  SymmetrizeTolerance 0.001
End

System
  Atoms
    Ne 0.0 0.0 0.0
  End
  Symmetrize Yes
End

task SinglePoint

Engine band
  Basis
    Core None
    Type GTO/CC-PV5Z
  end

  NumericalQuality VeryGood

  Dependency
     AllowBasisDependency True
     basis 1e-4
  End

  RIHartreeFock
    DependencyCoreRange 0.0
    FitGenerationDetails
      Method FromBasisProducts
      OneCenterDependencyThreshold 1e-08
    End
    FitSetQuality FromBasisProducts
  End

  SoftConfinement
     Quality Excellent
  End

  relativity 
     level None
  End

  usesymmetry False

  XC
    gga PBE
  end

  GW
     selfconsistency evGW
  END
EndEngine
eor