Example: single point for ammonia with TRIPOS¶

#!/bin/sh

#
# This is a technical example comparing analytical and numerical gradients for the Tripos forcefield
#
# The allowMissingParameters is a trick to run this molecule even though it is not fully supported by the definition file
#

for num in no yes
do

export AMS_JOBNAME=tripos3.num=$num

rm -rf $AMS_JOBNAME.results

$AMSBIN/ams << eor

Task SinglePoint
Properties Gradients=yes

EngineDebugging IgnoreGradientsRequest=$num IgnorePreviousResults=true

NumericalDifferentiation NuclearStepSize=1.0e-4


System
  Atoms
    N       0.00000000       0.00000000       0.26448000  ForceField.Charge=0.0  ForceField.Type=N.2
    H      -0.48379000       0.83795000      -0.08816000  ForceField.Charge=0.0  ForceField.Type=H
    H      -0.48379000      -0.83795000      -0.08816000  ForceField.Charge=0.0  ForceField.Type=H
    H       0.96758000      -0.00000000      -0.08816000  ForceField.Charge=0.0  ForceField.Type=H
  End

  BondOrders
         1 2 1.0
         1 3 1.0
         1 4 1.0
  End
End


Engine ForceField
  Type Tripos5.2
  AllowMissingParameters yes
EndEngine
eor

done