Example: Raman: NH3

Download Freq_NH3_RAMAN.run

#! /bin/sh

# Summary:
# - Analytical frequencies with subsequent calculation of Raman intensities in a
#   range
# - Numerical frequencies including all Raman intensities


# == Raman Intensities for Selected Frequencies ==

# The RamanRange keyword can be used to calculate Raman intensities for a range
# of frequencies only. Using this option is a fast alternative for the existing
# method of calculating Raman intensities, which is described in the second part
# of this example.

# Two values defining an interval of frequencies to calculate the Raman
# intensities for. The Raman intensities are calculated by numerical
# differentiation of the polarizability tensor. Only frequencies frequencies
# withing the interval that are known to be Raman-active will be included.


$ADFBIN/adf <<eor
  title NH3 frequencies with subsequent calculation of Raman intensities in the range 0-2000 cm-1
  atoms
    N       0.0000    0.0000    0.0000
    H       0.4729    0.8190    0.3821
    H      -0.9457    0.0000    0.3821
    H       0.4729   -0.8190    0.3821
  end
  Basis
    Type TZP
    Core Small
  End
  AnalyticalFreq
  end
  thermo  TMin=300 TMax=400
  BeckeGrid
    Quality good
  End
eor

mv TAPE21 NH3_freqs.t21

$ADFBIN/adf <<eor
  title NH3 Raman intensities in the range 0-2000 cm-1
  atoms
    N       0.0000    0.0000    0.0000
    H       0.4729    0.8190    0.3821
    H      -0.9457    0.0000    0.3821
    H       0.4729   -0.8190    0.3821
  end
  Restart 
    File NH3_freqs.t21
  End
  Fragments
    H t21.H
    N t21.N
  End
  RamanRange 0.0 2000.0
  thermo  TMin=300 TMax=400
  BeckeGrid
    Quality good
  End
eor


mv TAPE21 NH3_raman_range1.t21 

$ADFBIN/adf <<eor
  title NH3 Raman intensities in the range 2000-5000 cm-1
  atoms
    N       0.0000    0.0000    0.0000
    H       0.4729    0.8190    0.3821
    H      -0.9457    0.0000    0.3821
    H       0.4729   -0.8190    0.3821
  end
  Restart 
    File NH3_freqs.t21
  End
  Fragments
    H t21.H
    N t21.N
  End
  RamanRange 2000.0 5000.0
  thermo  TMin=300 TMax=400
  BeckeGrid
    Quality good
  End
eor
 
mv TAPE21 NH3_raman_range2.t21 


# == Raman Intensities for All Frequencies ==

# Raman scattering intensities and depolarization ratios for all molecular
# vibrations at a certain laser frequency can be calculated in a single run. The
# run type must be Frequencies and the RESPONSE key is used to specify that
# Raman intensities are computed.

# In this example the static Raman scattering is calculated (omega = 0). This
# type of calculation is very similar to an IR intensity calculation. In fact,
# all IR output is automatically generated as well. At all distorted geometries
# the dipole polarizability tensor is calculated. This is very time-consuming
# and is only feasible for small molecules.


$ADFBIN/adf <<eor
  title NH3 frequencies with Raman intensities
  atoms 
    N       0.0000    0.0000    0.0000 
    H       0.4729    0.8190    0.3821 
    H      -0.9457    0.0000    0.3821 
    H       0.4729   -0.8190    0.3821 
  end 
  Fragments 
    H t21.H 
    N t21.N
  End 
  geometry 
    frequencies
    End
  end 
  response
    raman
  end
  thermo  TMin=300 TMax=400 
  BeckeGrid
    Quality good
  End
eor
 
mv TAPE21 NH3_raman.t21