About having a text input for geometry optimisation with dihedral constrain

[xiki-tempula]

Is your feature request related to a problem? Please describe. I'm interested in using xTB for dihedral scan with torsiondrive.

Describe the solution you'd like I would like to have text input that contains coordinate, charge, multiplicity, the number of threads, dihedral constrain and possibly memory usage that could be fed to the xTB and allows me to perform geometry optimisation with dihedral constrain. It is kind of similar to other QM engines where one could use text input to control everything.

If possible state how you can assist in providing data or code to to implement the feature I could help to implement xTB in torsiondrive.

Additional context I was hoping that I could pass the input file into xTB in the form xtb --input default.inp

Where the default.inp is

$parallel
24
$end

$memory
30GB
$end

$charge
0
$end

$uhf
1
$end

$coord
    0.44060377782450   -0.01412168126920    0.18353526062450      C
    0.29759594746033    0.20416120151187    2.80401943168676      C
    2.63965610517835    1.02998458234760    3.68100113536889      C
    4.22999047646770    1.32233523397087    1.60243655937779      C
    2.87122906158385    0.67587612191465   -0.55901104575941      C
   -1.35063621036312   -0.20020256016136    3.96194626998985      H
    3.13809669169362    1.38388424380555    5.64254720998168      H
    6.18714478782806    1.94516496134903    1.65710127132652      H
    3.58252077369211    0.70464340056577   -2.48621742790732      H
   -1.07518151114132   -0.62376537124033   -1.06233682418088      H
$end

$opt
    # To indicate that this is an optimisation job
$end

$constrain
   dihedral: 3, 4, 1, 7, 180
$end

I wonder if this set of text input is available now and if this is something that could be done in the later release? Thank you.

[awvwgk]

Can torsiondrive be used together with xtb via QCEngine?

[xiki-tempula]

@awvwgk I have checked the dependency of torsion drive that it doesn't contain QCEngine, so I guess not? Apologise as I'm not too familiar with torsion drive myself and asking the repo owner to add a dependency could be difficult.

I could get around with the problem where the user provides a custom input file for torsion drive (in the format that I have used here) and I parse the custom input file to be the input for the xTB.

[awvwgk]

I asked in the MolSSI Slack, there seems to be a service via QCFractal to perform calculations with torsiondrive as well as some new development in https://github.com/MolSSI/QCEngine/pull/325 for this. It seems to be in principle possible via this venue.

I haven't used torsiondrive myself yet, so I don't know exactly what the requirements are.