# How to generate topology for Graphene molecule from .gro file using GROMACS program?

**URL:** <https://gromacs.bioexcel.eu/t/how-to-generate-topology-for-graphene-molecule-from-gro-file-using-gromacs-program/7879>\
**Category:** User discussions\
**Tags:** simulation-setup\
**Created:** [December 18, 2023, 11:31am UTC](https://gromacs.bioexcel.eu/t/how-to-generate-topology-for-graphene-molecule-from-gro-file-using-gromacs-program/7879 "2023-12-18T11:31:20Z")\
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**Author:** ![vikas28](https://avatars.discourse-cdn.com/v4/letter/v/9d8465/32.png) [@vikas28](https://gromacs.bioexcel.eu/u/vikas28)\
**Post date:** [December 18, 2023, 11:31am UTC](https://gromacs.bioexcel.eu/t/how-to-generate-topology-for-graphene-molecule-from-gro-file-using-gromacs-program/7879/1 "2023-12-18T11:31:20Z")

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GROMACS version: GROMACS/2022.4-fosscuda-2020b  
GROMACS modification: Yes/No  
Here post your question  
Greetings, everybody. I have generated a graphene sheet using the VMD program and saved the resulting file in the .gro format. Now I would like to use the GROMACS program to model the interaction between graphene and a solvent. To proceed, I require the topl.top and .itp files for my graphene sheet. If feasible, I would like to immobilize or freeze the graphene atoms prior to energy minimization in the simulation to avoid the folding or transfer of the graphene atoms. If somebody has developed such system, please guide me. I will be highly thankful to you.