VMD-L Mailing List

From: Joel Subach (mjsubach_at_alumni.ncsu.edu)
Date: Fri Oct 13 2023 - 06:52:49 CDT

Hello VMD Community, towards the above topic:

Via the ffTK Opt Torsions Tab to optimize dihedral parameters (Tutorial 6.2
link: *https://www.ks.uiuc.edu/Training/Tutorials/science/ffTK/fftk-tutorial.pdf
<https://www.ks.uiuc.edu/Training/Tutorials/science/ffTK/fftk-tutorial.pdf>).*

I had clicked Run Optimization after inputting:

all of the proper files i.e. psf, pdb, par for the *input section *

my 4-output.out resulting files generated via ORCA for the *QM Target Data
Section*

and my atom types for my two-dihedral angles for the *Dihedral Parameter
Settings*

the below error states:
FATAL ERROR: UNABLE TO FIND IMPROPER PARAMETERS FOR CG2O2 CG2R51 OG2D1
OG311 (ATOMS 17 7 37 36)
[Partition 0][Node 0] End of program
FATAL ERROR: UNABLE TO FIND IMPROPER PARAMETERS FOR CG2O2 CG2R51 OG2D1
OG311 (ATOMS 17 7 37 36)

(See complete Application_Error.log file attached and note within it
the: *Info:
0 IMPROPER*
may have been generated via ffTK?)

Below is a paste of the impropers from my generated .par file:

IMPROPER
!
!V(improper) = Kpsi(psi - psi0)**2
!
!Kpsi: kcal/mole/rad**2
!psi0: degrees
!note that the second column of numbers (0) is ignored
!
!atom types Kpsi psi0
!

* Note i skipped to Scan Torsions since that was all I needed amended i.e.
I skipped
Opt. Charges etc. tabs if this would amend the Improper Values, this may
make no difference I believe it should not.

For my Opt Torsions `Dihedral Parameter Settings´ i used the Default Values
for Force Constant, Periodicity, Phase Shift Lock Phase (0, 1, 0, no
respectively).

Please let me know how this Fatal Error could be amended to successfully
generate the
Run Optimization? Thanks if you know:), Joel 🚀