# Example: Restart analytical Hessian calculation¶

Download HessianRestart.run

#!/bin/sh

# This example demonstrates how one can complete an analytical Hessian calculation
# in three steps without re-doing CPKS for all atoms and the subsequent steps.
# We will define regions for the first and second steps right away.
# Note that the region for the second step includes atoms of the first one.
# This is necessary because we want the resulting Hessian in the subsequent steps
# to include the atoms done in the previous calculations.
# First, we calculate the Hessian sub-matrix corresponding to the C atoms.

AMS_JOBNAME=step1 "$AMSBIN/ams" << eor Task SinglePoint Properties NormalModes Yes SelectedRegionForHessian step1 End System Atoms C -2.711485799381603 -2.593393872048840 -0.00016442137955 region=step2,step1 C -1.846368848888818 -1.340467404429865 0.00016453093935 region=step2,step1 H -2.203636997435432 -3.429266061978078 -0.51549899454129 region=step2 H -3.673159561801013 -2.414816382275922 -0.51564516686341 region=step2 H -2.938101685663578 -2.921829124623212 1.03094752484358 region=step2 H -0.884694282363284 -1.519047266416641 0.51564280107136 H -2.354216233206031 -0.504595127574485 0.51550071600252 H -1.619753333793463 -1.012031055604717 -1.03094699007257 End BondOrders 1 2 1.0 1 3 1.0 1 4 1.0 1 5 1.0 2 6 1.0 2 7 1.0 2 8 1.0 End End Engine ADF save TAPE13 EndEngine eor # In the second calculation, we add the Hessian sub-matrix corresponding to H atoms # of the first methyl group. We use as much data as possible from the first one. # This includes the part of the analytical Hessian computed for atoms of the "step1" # region in the previous calculation. # We use the adf.rkf file for restart but if the 1st calculation had crashed or # stopped uncontrollably, we would have to use the TAPE13 file instead. # AMS_JOBNAME=step2 "$AMSBIN/ams" << eor

Properties
NormalModes Yes
SelectedRegionForHessian step2
End

File step1.results/ams.rkf
End

eor

# In the third calculation, we do not use the SelectedRegionForHessian key, because
# we want the full Hessian. In this calculation we use data from the second step.

AMS_JOBNAME=step3 "\$AMSBIN/ams" << eor