Example: Rescan frequencies: NH3
********************************

"Download Freq_NH3_Scan.run"

   #! /bin/sh

   # Sometimes spurious imaginary frequencies are calculated where one would expect
   # a very low (nearly zero) frequency. Most frequently this happens when there is
   # a barrier-free rotation of, for example, methyl groups. The VibrationalAnalysis 
   # task (using ModeRefinement) allows one to rescan calculated frequencies in order 
   # to find out if they were calculated accurately.

   # In this example analytical frequencies are calculated. Next recalculation of
   # certain NH3 frequencies are performed by scanning along normal modes from a
   # restart file. In this calculation the frequencies are calculated numerically
   # with finite displacements using symmetry.

   AMS_JOBNAME=NH3 $AMSBIN/ams <<eor
   System
     Symmetrize Yes
     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
   end

   Task SinglePoint

   Properties
     NormalModes Yes
   End

   Engine ADF
     title NH3 analytic frequencies
     beckegrid quality=Good
     basis
       type TZP
       core Small
     end
   EndEngine
   eor

   AMS_JOBNAME=ScanFreq $AMSBIN/ams <<eor
   LoadSystem 
     File NH3.results/adf.rkf
   End
   LoadEngine NH3.results/adf.rkf

   Task VibrationalAnalysis

   VibrationalAnalysis
       Type ModeRefinement
       NormalModes
          ModeFile NH3.results/adf.rkf
          ModeSelect
             FreqRange 0 4000
          End
       End
   End
   eor
