Example: Calculation of overlap of primitive basis functions¶

#! /bin/sh


# Example for calculating overlaps of primitive basis functions for almost
# coinciding nuclear coordinates, using the key CALCOVERLAPONLY. ADF will stop
# after the calculation of these overlaps. The overlap is printed in the output,
# but is also present on TAPE15 in binary format in Matrices%Smat.
# Could be useful for external programs like SHARC.

$AMSBIN/ams <<eor
System
  atoms
     C     0.1662008   -0.0114225   0.0220295  region=one
     S     1.7387976    0.003246   -0.0021948  region=one
     H    -0.3207087    0.9655128  -0.0963368  region=one
     H    -0.479404    -0.9324828  -0.0963367  region=one
     C     0.167746    -0.0109425   0.0203042  region=two 
     S     1.7382268    0.002927   -0.0020154  region=two 
     H    -0.329981     0.9728265  -0.0893183  region=two 
     H    -0.4704213   -0.9353924  -0.088502   region=two
  end
  # Prevents AMS from stopping in case of almost-coinciding nuclei
  AllowCloseAtoms True
end

Task SinglePoint

Engine ADF
  Title CH2S overlap of near identical geometries
  CalcOverlapOnly
  Basis
    Type DZP
    Core None
  End
  Print SMAT
  Save TAPE15
EndEngine

eor