# MMPBSA for custom atom types

**URL:** <https://gromacs.bioexcel.eu/t/mmpbsa-for-custom-atom-types/12405>\
**Category:** User discussions\
**Tags:** analysis-tools\
**Created:** [July 20, 2025, 7:57am UTC](https://gromacs.bioexcel.eu/t/mmpbsa-for-custom-atom-types/12405 "2025-07-20T07:57:33Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![AndriiLesiuk](https://avatars.discourse-cdn.com/v4/letter/a/eada6e/32.png) [@AndriiLesiuk](https://gromacs.bioexcel.eu/u/AndriiLesiuk)\
**Post date:** [July 20, 2025, 7:57am UTC](https://gromacs.bioexcel.eu/t/mmpbsa-for-custom-atom-types/12405/1 "2025-07-20T07:57:33Z")

</div>

GROMACS version:2024.3  
GROMACS modification: No  
Hi all. Could you please help me with mmpbsa tool for interaction energy analysis. I performed simulation of a protein with tio2 nanoparticle in charmm27 ff. Now I need to process the data with mmpbsa, but encountered a problem with custom atom types (Ti and O atoms of the NP), namely how to indicate their parameters properly to get correct prmtop file?