Hello! I am new in the field of Molecular Dynamics. I am trying to create a model of the single-layer graphene sheet using Material Studio software. I am writing the steps below that I followed to create the model.

1. "Graphene.xsd" file is imported into Material Studio.

2. Using "Supercell" from "Symmetry" in the "Build" menu I made a single-layer graphene sheet.

3. "Geometry Optimization" is done on the model using the "Forcite Module"

4. "NVT" ensemble is selected from "Dynamics" and the simulation is performed at room temperature.

5. "Anneal" is performed to make the model stress-free.

6. "NPT" ensemble is selected from "Dynamics" and the simulation is performed at atmospheric pressure.

Following all these steps, the density obtained for the model is much less than the experimental density value.

What is the reason behind that? Am I doing anything wrong during the simulation? How can I achieve the model density near the experimental value?

Please explain in detail mentioning the steps to be followed.

Thank you so much.