fixed: failed image creation in periodic hops

[RobertaPascazio]

Summary

If the two images only differ by periodicity (e.g., the coordinates of the working ion in the two images are (x,y,z) and (x+a,y,z)), pymatgen/analysis/diffusion/neb/pathfinder.py crashes because it can't interpolate between the endpoints, causing a ValueError.

This fix catches the exception and avoids crashing in get_images_and_relax.

Checklist

• All linting and tests passed in pre-commit.

[esoteric-ephemera]

Sorry missed this, can you take a look at the fallback to linear interpolation here and let me know if you think that's suitable?

[RobertaPascazio]

So two things:

1. interpolate does not work on periodic sites, it's a Structure property. the correct script would be:

    except ValueError:
        # NEBPathfinder can fail, fall back to linear interpolation if that occurs
        all_images = pf_struct_ini.interpolate(
            pf_struct_fin, nimages=n_images + 1, autosort_tol=0.5
        )

2. Unfortunately running interpolate on two "periodic" structures returns the same structure n_images times (I tried it and checked the working ion coordinates).

[esoteric-ephemera]

Makes sense to me - added a missing continue to your change. Take a look and I'll merge once you OK it