From: Bassam Haddad (
Date: Tue Sep 21 2021 - 10:34:26 CDT

Hi Mariano,

Thank you for your reply. I was able to resolve the issue by installing
orca_4.1.1 (the version in the ffTK tutorial). My issues were with
orca_5.0.0.. I hadn't run anything differently, so I assume it was an error
due to version differences.


On Sun, Sep 19, 2021 at 8:20 PM Mariano Spivak <> wrote:

> Hi Bassam,
> The bond/angle optimization step in FFTK using ORCA generates one input
> file (e.g. hess.inp) that contains two calculations in sequence, the file
> “initial.hess” is generated by the first calculation.
> The error you see ORCA report is most likely due to from some error
> termination in the first calculation (e.g. issues with memory, not
> converged).
> Try repeating the calculation or you can send the generated files and I
> can take a look at the issue.
> Hope this helps.
> Best
> On Sep 18, 2021, at 11:02 AM, Bassam Haddad <> wrote:
> Hello again,
> In an attempt to trouble-shoot my previous problems, I performed the ffTK
> tutorial using the .psf/.pdb/.par from the tutorial files. The charge
> optimization step worked, which tells me that there is an issue with the
> way that CHARMM-GUI generated the .psf of my ligand.
> I did however run into another problem, however, while running the
> tutorial files (ETOH). When I went to run the bond and angle optimization,
> ORCA threw an error saying it needed "initial.hess" as an input and could
> not find it. "initial.hess" is not generated when using the "Write QM
> Inputs" function in the ffTK GUI. Where can we find/build initial.hess for
> our own calculations?
> Thank you for your time!
> Bassam
> On Mon, Sep 13, 2021 at 12:38 PM Bassam Haddad <> wrote:
>> Hello All,
>> I am currently trying to parameterize a small molecule using fftk on
>> vmd_1.4a51, with ORCA, and I ran into an error preceding charge
>> optimization:
>> `ERROR) No molecules loaded.mol addfile operates on one molecule only`
>> Though the .psf and .pdb are loaded. All ORCA inputs were generated in
>> ffTK, and orca ran without error. I have seen this error pop-up on the mailing
>> list before
>> <>however
>> it appears to be an unrelated issue, as I am not using Gaussian, and don't
>> appear to have errors from ORCA. I would appreciate any assistance you can
>> provide in overcoming this error.
>> I have attached the error logs.
>> Thank you for your time!
>> ________________________
>> *Bassam Haddad, Ph.D.*
>> Post-Doctoral Researcher
>> Forschungszentrum Juelich