Example: Numerical Frequencies: NH3
***********************************

"Download Freq_NH3.run"

   #! /bin/sh

   # Summary:
   # - Frequencies with symmetric displacements
   # - Frequencies with Cartesian displacements
   # - Isotope effects in the frequencies

   # == Frequencies with symmetric displacements ==

   # Computation of frequencies by symmetric displacements. The assumed equilibrium
   # input structure should be given in Cartesian coordinates.

   # The symmetry is determined automatically by the program as C(3v), from the
   # input coordinates. During the calculation first symmetric atomic displacements
   # are constructed. The number of such displacements in each irreducible
   # representation corresponds to the number of frequencies with the corresponding
   # symmetry. All displaced geometries within one representation have the same
   # symmetry, which enables us to use it to speed up the computation
   # significantly. 

   AMS_JOBNAME=NH3_symm $AMSBIN/ams <<eor
   System
     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
     Symmetrize Yes
   end

   Task SinglePoint

   Properties
     NormalModes Yes
   End

   NormalModes
     Displacements Symmetric
   End

   Thermo
     Temperatures 300:400:10
   End

   Engine ADF
     title NH3 frequencies in symmetric displacements
     BeckeGrid 
       quality good
     End
     Basis 
       type TZP 
       core Small
     End
   EndEngine
   eor


   # == Frequencies with Cartesian displacements ==

   # Computation of frequencies by Cartesian displacements. The assumed equilibrium
   # input structure is given in internal coordinates. 

   AMS_JOBNAME=NH3_cartesian $AMSBIN/ams <<eor
   System
     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
     Symmetrize Yes
   end

   Task SinglePoint

   Properties
     NormalModes Yes
   End

   NormalModes
     Hessian Numerical
     Displacements Cartesian
   End

   Thermo
     Temperatures 300:400:10
   End

   Engine ADF
     title NH3 frequencies
     BeckeGrid 
       quality good
     End
     Basis 
       type TZP 
       core Small
     End
   EndEngine
   eor


   # The symmetry is determined automatically by the program as C(3v), from the
   # input coordinates. In a Frequencies calculation the symmetry (specified on
   # input or computed internally) is used for analysis and in some cases to speed
   # up the calculation.

   # The equilibrium coordinate values are supplied as identifiers that are
   # associated with values in the define block.

   # The key thermo addresses the thermodynamical analysis (only available in a
   # Frequencies calculation, otherwise ignored). The specification Temperatures 300:400:10
   # means that the thermodynamic properties are printed for the temperature range
   # 300-400K using 10 equidistant steps and for a pressure of 1.0 atmosphere
   # (default).

   # Frequencies calculations suffer easily from numerical inaccuracies. Therefore,
   # the default numerical integration precision in a Frequencies calculation is
   # higher than in an ordinary single-point or minimization run.


   # == Isotope effects in the frequencies ==

   # Calculate a different isotope of H, in this case deuterium.

   AMS_JOBNAME=Isotope $AMSBIN/ams <<eor
   System
     atoms
        N   0.0000    0.0000    0.0000
        H   0.4729    0.8190    0.3821 mass=2.014
        H  -0.9457    0.0000    0.3821 mass=2.014
        H   0.4729   -0.8190    0.3821 mass=2.014
     end
     Symmetrize Yes
   end

   Task SinglePoint

   Properties
     NormalModes Yes
   End

   NormalModes
     Hessian Numerical
     Displacements Cartesian
   End

   Thermo
     Temperatures 300:400:10
   End

   Engine ADF
     title NH3 frequencies
     BeckeGrid 
       quality good
     End
     Basis 
       type TZP 
       core Small
     End
   EndEngine
   eor
