Voronoi Analysis

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1

Dear Lammps-users,

I want to use voronoi/atom in Lammps to get the nearest neighbor number, nearest neighbor list, i.e, the ID of all nearest neighbors for each atom in my configurational cell.

Atom Eye shows that the nearest neighbor number is 4-6, which is reasonable. However, the Voronoi result shows that the nearest neighbor number is 11-24, which is so large and obviously unreasonable. But the atomic volume resulted from the Voronoi analysis is reasonable.

My input command look like following:

compute AtomicVolume all voronoi/atom peratom yes

dump AtomicVolume all custom 10 volume.*.E11.txt id c_AtomicVolume[1] c_AtomicVolume[2]

compute V1 all voronoi/atom neighbors yes

dump V1 all local 1 InitialVoronoi.E11.txt index c_V1[1] c_V1[2] c_V1[3]

run 0

Both of these show the nearest neighbor count is 11-24.

Is there something wrong?

Thanks,

Zhao

2

The number of neighbours in a Voronoi construction is the number of faces of the polyhedra. For some lattices the number of faces fluctuates a lot (e. g. square or cubic) . You can specify an area threshold so that only faces with an area larger than the threshold are considered neighbours, perhaps that will remove the issue.

3

Hi Stefan,

Thank you very much for your response. It’s very useful.

Is there any good method to determine the best area threshold, which could generate the truth nearest neighbor count? Or we have to try many times and compare the results?

All the best,

Zhao