Re: ffTK torsion scan convergence using Gaussian.

From: Gumbart, James C (
Date: Tue Nov 13 2018 - 20:04:59 CST

(Make sure to copy the list on replies)

Off the top of my head, I don’t recall what that error means. Sorry!


On Nov 13, 2018, at 9:03 PM, Dipak Balasaheb Sanap <<>> wrote:

Hi, thank you for the suggestion. I did load the visualise the log file using QMTools. It looks fine.

I am not understanding while the rerun from the checkpoint file dosent start. As mentioned above, it gives me an error like "ONIOM results not found on unit 2."

Do you have any suggestion to restart the run, I just want to give it a shot. Thanks.

On Tue, 13 Nov 2018, 8:56 p.m. Gumbart, James C <<> wrote:
I would guess that it’s a high-energy state, which means you don’t actually need to scan it. FFTK is set to ignore energies above 10 kcal/mol by default anyway. But definitely load the log file and check.


> On Nov 12, 2018, at 7:08 PM, Dipak Balasaheb Sanap <<>> wrote:
> Dear all,
> I am trying to parameterize an organic molecule using ffTK. Things run smooth for everything except torsion scan for 1 dihedral. Reading log file suggest that optimization is not converging, I get the following error in log file.
> Predicted change in Energy=-1.997999D-02
> Optimization stopped.
> -- Number of steps exceeded, NStep= 120
> -- Flag reset to prevent archiving.
> After reading few threads on various mailing lists, I did try few things as follows:
> 1. Changed the MaxCycles=1000
> # opt (modredundant,MaxCycles=1000) MP2/6-31g(d) Geom=PrintInputOrient
> 2. Tried restart from the existing checkpoint file. Input file for restart as follows:
> %NoSave
> %chk=FRA.scan9.pos.chk
> %nproc=36
> %mem=406GB
> #opt (modredundant,Restart,MaxCyc=1000) MP2/6-31g(d) Guess=Read Geom=Checkpoint
> Error for restart:
> Restoring state from the checkpoint file "FRA.scan9.pos.chk".
> ONIOM results not found on unit 2.
> I am, attaching the input file any suggestion would be really useful.
> I have also visualized the log file using QM tools, nothing looks broken.
> Dipak Sanap
> PhD in Chemistry,
> University of Delaware.
> <FRA.scan9.pos.gau>

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