Example: Calculating the atomic forces

Download BNForce.run

#!/bin/sh 

# This example shows how to calculate the gradient of the energy with respect to
# atomic displacements, using the GRADIENTS key block. For more details on
# consult the documentation for Gradients.

$ADFBIN/ams <<eor

Task SinglePoint

System
   Atoms 
    B   0.0 0.0 0.0 
    N   0.86544 0.86544 0.86544 
   end 
   Lattice  
     0.0 1.8 1.8 
     1.8 0.0 1.8 
     1.8 1.8 0.0  
   End
End

Properties
  Gradients True
End

Engine Band
   Title BN zincblende structure (force calculation)

   NumericalQuality Basic  ! for speed, not very accurate

   Basis
      Type TZ2P
      Core Large
   End
EndEngine

eor

# In the output you will find the result
# FINAL GRADIENTS
#    1  B  0.017517  0.017517  0.017517
#    2  N -0.017517 -0.017517 -0.017517