4
$\begingroup$

I have been exploring xtb and used it to run docking on an ion pair. I get the message at the end in the .log file. The xyz files of input structures were obtained from Gaussian output files. Is there a way to optimize monomers using xtb before submission so that the interaction energies output are deemed physical? I am unsure of how to solve this issue. All advice is highly appreciated.

Thank you,

 Interaction energies
 Attention: monomers are not optimized
 Interaction energies are not physical
Improve this question
$\endgroup$
2
  • $\begingroup$ I think that the docking module should be used only to have starting structures for further complex optimization. $\endgroup$
    – Camps ♦
    Jun 12 at 13:43
  • $\begingroup$ Thanks! That's my goal as well – however, I was not sure if there's something that I am missing in terms of using xtb. $\endgroup$
    – bhopshang
    Jun 12 at 16:58

1 Answer 1

Reset to default
3
$\begingroup$

The error message states

Interaction energies

Attention: monomers are not optimized

Interaction energies are not physical

This suggests that the interaction energy is computed as E(interaction) = E(aggregate) - sum[E(monomer)]. The true interaction energy is the difference of the optimized aggregate to the optimized monomers. Looking into the source code, this warning arises at

https://github.com/grimme-lab/xtb/blob/0e66cab758133bcaa6ea2bb59012a1603166e6fd/src/docking/search_nci.f90#L964

The warning appears to be issued always, suggesting that it is just to inform you that the interaction energy estimates are not accurate.

Improve this answer
$\endgroup$

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .