Re: [AMBER] QM/MM with Orca: selected input parameters not taken into account

From: James Kress <>
Date: Thu, 8 Mar 2018 12:03:15 -0500

What does the whole Orca output look like?

Your SCF is not converging but one would need to look at the complete Orca output file to see what's going on and suggest a solution.


-----Original Message-----
From: Ruth Helena Tichauer <>
Sent: Thursday, March 08, 2018 4:55 AM
To: AMBER Mailing List <>
Subject: [AMBER] QM/MM with Orca: selected input parameters not taken into account

Dear Amber users and developers,

I’m trying to perform a QM/MM molecular dynamics simulation of a protein complex using the following input files:
M/MM minimization using Orca
  maxcyc=10000, ncyc=9000,
  ntpr=20, ntwx=20, ntwr=2000, ioutfm=1,
  ntr=1, restraint_wt = 5.0,
  restraintmask = ':170,185,.CA,C,N',

#ORCA input file
SOSCFStart 0.00033

I’m puzzled since in the mdout file, the chosen parameters are correct:
| basis = DEF2-SVP
| cbasis = DEF2-SVP
| jbasis = DEF2-SVP
| method = PBE
| convkey = SLOPPYSCF
| guess = read
| scfconv = -1
| grid = 4
| finalgrid = 6
| maxiter = 500
| maxcore = 1024
| ntpr = 20
| num_threads = 1
| debug = 0
| dipole = T
| use_template = T
| /

but when I look at the orc_job.dat file, because the simulation crashes with the following error message:

     This SCF-wavefunction IS NOT FULLY CONVERGED!
     You can't use it for properties or numerical calculations !
     Aborting the run ...
     Please restart calculation (with larger maxiter/different convergence flags)

I see that the SCF stopped after 125 cycles and that the energy threshold is not the one I have selected:

               * ERROR *
               * SCF NOT CONVERGED AFTER 125 CYCLES *

  Last Energy change ... 3.4826e-05 Tolerance : 1.0000e-08
  Last MAX-Density change ... 1.7469e-03 Tolerance : 1.0000e-07
  Last RMS-Density change ... 1.0077e-05 Tolerance : 5.0000e-09
  Last DIIS Error ... 1.1837e-03 Tolerance : 5.0000e-07

             **** DENSITY FILE WAS UPDATED (orc_job.scfp.tmp) ****
             **** ENERGY FILE WAS UPDATED (orc_job.en.tmp) ****

     The wavefunction IS NOT YET CONVERGED! It shows however signs of
     convergence. Therefore the wavefunction will be stored and can be
     used as input for another calculation.

What should I do in order for Orca to take into account the parameters I select with my input files and not the default ones? If I provide the orc_job.tpl file, should I re-define all my parameters in it (and not only the additional ones)?

Thank you for any insight into this matter.


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Received on Thu Mar 08 2018 - 09:30:03 PST
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