Building graphene shell in VNL

[carbn9]

Hi,

I need to build the graphene shell shown in the second or the final step of the following image:



which is from the publication of http://www.sciencedirect.com/science/article/pii/S0021999111007042

I know and I can build a graphene sheet with NanoSheet command and I studied the corresponding tutorial. However could you please help me for connecting upper and lower graphene sheets to form a shell like structure?

Best regards,
Maresh

[Anders Blom]

Well now - that's hardly trivial...

You may be better off starting with a nanotube, and deform it into an ellipsoidal shape by compressing the cell in one direction while keeping the fractional coordinates fixed. Then maybe you can try "Coordinate Tools>Transform by Expression" to squeeze the edge... In a sense you just need a good starting guess, you will need a geometry optimization in the end anyway.

Good luck!

[carbn9]

Thanks Anders Blom.

"deform it into an ellipsoidal shape by compressing the cell in one direction while keeping the fractional coordinates fixed" Sorry but how to do this? 

Best regards and fingers crossed...

[Nordland]

I tried to play around with builder, and you can quite easily build something like this.

It is not perfect, but it is possible to this operation.

[carbn9]

Thanks Nordland. The structure you built seems really good.

One thing: In the builder, which menu should I use? Or is there a tutorial on this?

Thanks again...

[Nordland]

I have tried it a couple of times and since I made the screenshots I have made it even better,
but the approach is exactly the same. The way I see it, it can be approached as building a graphene box,
and then followed by a relaxation with the Brenner potential.

• Start by making a huge graphene ribbon.
• Clip of a part of each sides - this will effect determine the height of the shell.
• Select one of the flips.
• Rotate it using the move tool to be orthogonal on the sheet.
• Repeat for the other flip.
• Select the long part as shown in picture.
• Rotate this 90 degrees such that it points in the same directions as the flips.
• I connected it to a molecule ( Just for avoid the box around the system )
• Select the top part, and rotate it 90 degrees to put the top down.
• Almost done!
• Select the last flip and rotate it 90 degrees. The box is now closed.
• Remove any surplus atoms
• The box is done.
• Using the quick optimizer many many times you get your shell structure

Warning heavy image load incoming !