Gold nanoparticle coupled with graphene

[ft.nima]

Hello
Dear all,
I want to simulate optical properties of graphene coupled with gold nanoparticles.How can I build  gold nanoparticles on graphene surface structure?I build Gold nanoparticle,then i put it on graphene and when i optimize this structure,gold nanoparticle atoms diffuse on graphene.I mean it lose nanoparticles shape.

Thank you very much for your time and kind help

[berna]

Hi. You can tag gold atoms. Then you should look constraint editor options in geometry optimization plugin. You will see tagged atoms. Fixing these atoms is a solutions.

[Anders Blom]

Or better yet, making them a "rigid body", that way they stay together in the desired shape, however the entire nanoparticle can move.

[ft.nima]

Dear Berna
How can I fixed them?I will be Thankful If you explain

[berna]

Hi. I hope I could help you. My structure has no sense but an example.
Step 1- Create your structure (step1.png)
Step 2- Select gold atoms and tag them by selection tools (step2.png)

[berna]

Step 3- Send the structure to scrip generator (step3.png)

[berna]

Step 4- OptimizeGeometry ---> Atomic Constraint Editor (step4.png)
(Sorry, all files are too large to send one post)

[ft.nima]

 Dear berna and Anders blom
Thank you so much