[RMCProfile-users] Potentials

[giles.flowitt-hill at stfc.ac.uk]

Hi Min,

The best way I have found is to look at the energies in molecular dynamics force fields as starting points for RMC potential energies. You will need to make sure the energies you take from the force field are in the same form as the RMC potentials though.

As for distances and angles, I would suggest that you use the geometry from your Rietveld refinement and see how those work with creating a good fit in the low-r region.

Generally though, I would be tempted to ask if potentials are the best thing for you to use?

In RMCProfile potentials are assigned once per refinement, this links pairs of atoms together for the duration of the refinement. So if you are using refinement protocols such as site swapping, the potentials will prevent this sort of move from happening.

Personally, I would not suggest using the potentials restraints for anything other than molecular systems as RMCProfile contains many other restraint types that may be more appropriate for alloys and glasses.

All the best,
Giles

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