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Counting irradiation defects inside the grain interior

Hi, Alex

I try to count the number of irradiation defects (interstitial & vacancy) inside each grain of my poly-crystal model by W-S method. The displaced configuration is the target grain, pretreated (like translation and rotation) before applying the W-S analysis. The reference configuration is a large enough perfect crystal. As shown in the attached figure(colored by occupancy) , the number of interstitials can be counted well. As for the vacancy, although they are also identified but i can obtain they numbers since all those sites outside the grain are also has a property of "occupancy==0"

Clearly, this problem is rooted in?the boundary?of grain?is undefined. Then I noticed that the “construct surface mesh" modifier could generate a surface for a grain. Is it possible to use this surface as the boundary of grains? Then maybe the vancancy number can be obtain by a Selection like "inside the surface == True" && "occupancy==0". How can I achieve this by OVITO?

Uploaded files:


I'm not sure if I understood your question correctly, but my suggestion would be to use a Compute property modifier with the settings shown in attached screenshot to select (and count) only vacancy sites inside the grain. The idea is to check if a vacancy site has not more than 2 other direct neighbors that are also vacancy sites. You might want to play around with these settings.


Uploaded files:
  • selection.png

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